Exhibit 4.20



Final Form



FORM OF LOCK-UP AGREEMENT



This Lock-up Agreement (this
“Agreement”) is entered into as of February [_], 2024, by and between Critical Metals Corp., BVI business company incorporated
in the British Virgin Islands (“PubCo”) and the undersigned (“Holder”). PubCo and the Holder
and their respective successors and permitted assigns are sometimes collectively referred to herein as the “Parties”,
and each of them is sometimes individually referred to herein as a “Party”. Capitalized terms used but not defined
herein shall have the respective meanings ascribed to such terms in the Merger Agreement (as defined below).



RECITALS



WHEREAS, Sizzle Acquisition
Corp., a Delaware corporation (“SPAC”), European Lithium AT (Investments) Limited, a BVI business company incorporated
in the British Virgin Islands and a direct, wholly-owned subsidiary of EUR (the “Company”), European Lithium Limited,
an Australian Public Company limited by shares (“EUR”), PubCo and Project Wolf Merger Sub Inc., a Delaware corporation
and a direct, wholly-owned subsidiary of PubCo (“Merger Sub”), entered into an Agreement and Plan of Merger, dated
as of October 24, 2022 (as amended on January 4, 2023, July 7, 2023, November 17, 2023 and as it may be further amended, restated, supplemented
or otherwise modified from time to time, the “Merger Agreement”);



WHEREAS, pursuant to and in
accordance with the Merger Agreement, subject to the terms and conditions thereof, upon the consummation of the transactions contemplated
by the Merger Agreement, among other matters, (i) Merger Sub will merge with and into the SPAC, with the SPAC continuing as the surviving
corporation and a wholly-owned subsidiary of PubCo, and as a result of which, all of the issued and outstanding shares of common stock,
par value $0.0001 per share (the “SPAC Shares” ), of the SPAC will be replaced with PubCo Shares and all of the
issued and outstanding warrants to purchase SPAC Shares will be replaced with substantially similar warrants of PubCo, in each case, on
a one-for-one basis, (ii) EUR will transfer to PubCo all of the issued and outstanding equity interests of the Company in exchange for
newly issued shares of PubCo and (iii) the SPAC and the Company will become wholly-owned subsidiaries of PubCo (the transactions contemplated
by the Merger Agreement, the “Transactions”);



WHEREAS, PubCo, SPAC, and
VO Sponsor LLC, a Delaware limited liability company, and the subscribers named therein (the “Subscribers”) have entered
into a Subscription Agreement (the “Subscription Agreement”), pursuant to which such Subscribers, upon the terms and
subject to the conditions set forth therein, have agree to purchase PubCo Shares in a private placement (the “PIPE Investment”)
to be consummated contingent upon, and immediately prior, to the Effective Time;



WHEREAS, as of immediately
after the Effective Time, Holder will be the holder of record and beneficial owner (as such term is defined in Rule 13d-3 promulgated
under the Exchange Act), with the sole power to dispose of (or sole power to cause the disposition of) and the sole power to vote (or
sole power to direct the voting of) the Lock-up Shares (as defined below); and



WHEREAS, in connection with
the Transactions and the PIPE Investment, the Parties desire to enter into this Agreement, pursuant to which the Lock-up Shares shall
become subject to the limitations on disposition as set forth herein.













NOW, THEREFORE, in consideration
of the foregoing and the mutual representations, warranties and covenants, and subject to the conditions, herein contained, and intending
to be legally bound hereby, the Parties hereby agree as follows:



Article
I
Introductory Matters



Section 1.01	Defined
Terms. In addition
to the terms defined elsewhere herein or defined under the Merger Agreement, the following terms have the following meanings when used
herein with initial capital letters:



“Covered Shares”
means all the PubCo Shares owned by a Holder from time to time, including any PubCo Shares issued as part of bonus share issuances, dividends
and distributions and any securities into which or for which any or all of the Covered Shares may be changed or exchanged or which are
received in any recapitalization, share exchange, share conversion or similar transactions.



“Immediate Family”
means with respect to any Person, such Person’s spouse or partner (or former spouse or former partner), siblings (whether by blood,
marriage or adoption) and his or her spouse, descendants and ascendants (whether by blood, marriage or adoption) and his or her spouses
and siblings.



“Lock-up Period”
means the period beginning on the Closing Date and ending on the date that is the earlier of (i) twelve (12) months after the Closing
Date and (ii) the date after the Closing Date on which PubCo consummates a third-party tender offer, stock sale, liquidation, merger,
share exchange or other similar transaction with an unaffiliated third party that results in all of PubCo’s shareholders having
the right to exchange their equity holdings in PubCo for cash, securities or other property.



“Lock-up Shares”
means with respect to a Holder or each of its Permitted Transferees, any Covered Shares (i) held by it immediately after the Effective
Time or issued or issuable to the Holder in connection with the Transactions and (ii) issued to such Holder in connection with the exercise
or settlement of any SPAC Warrant or PubCo Warrant held by it immediately after the Effective Time, in each case, together with any securities
paid as dividends or distributions with respect to such securities or into which such securities are exchanged or converted.



“Permitted Transferees”
means, prior to the expiration of the Lock-up Period, any Person to whom a Holder or any Permitted Transferee of such Holder is permitted
to Transfer PubCo Shares pursuant to Section 2.01(b) or Section 2.01(c).



“Transfer”
means the (A) sale of, public offer to sell, entry into a contract or agreement to sell, hypothecation or pledge of, grant of any option
to purchase or otherwise disposition of or agreement to dispose of, in each case, directly or indirectly, or establishment or increase
of a put equivalent position or liquidation with respect to or decrease of a call equivalent position with respect to, any security, (B)
entry into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership
of any security, whether any such transaction is to be settled by delivery of such securities, in cash or otherwise or (C) public announcement
of any intention to effect any transaction specified in clause (A) or (B).





2







Article
II
LOCK-UP



Section 2.01	Lock-up.



(a) Subject
to the exclusions in Section 2.01(b) and Section 2.01(c) each Holder, severally (and not jointly and severally), agrees
not to Transfer any Lock-up Shares until the end of the Lock-up Period (the “Lock-up”).



(b) Notwithstanding
the Lock-up restrictions set forth in Section 2.01(a), each Holder may Transfer any Lock-up Shares it holds during the Lock-up
Period: (i) to any direct or indirect partners, members or equity holders of such Holder, any Affiliates of such Holder or any related
investment funds or vehicles controlled or managed by such Persons or their respective Affiliates; (ii) by gift to a charitable organization;
(iii) in the case of an individual, by gift to a member of the individual’s Immediate Family or to a trust, the primary beneficiaries
of which are one or more members of the individual’s Immediate Family or an Affiliate of such Person; (iv) in the case of a trust,
to the trustor or beneficiary of such trust or the estate of a beneficiary of such trust; (v) in the case of an individual, by will or
other testamentary document or device or by virtue of laws of descent and distribution upon death of the individual; (vi) in the case
of an individual, pursuant to a qualified domestic relations order; (vii) with the prior written consent of PubCo; (viii) in connection
with a liquidation, merger, stock exchange, reorganization, tender offer, takeover offer, scheme of arrangement or other similar transaction
which results in all of PubCo’s shareholders having the right to exchange their PubCo Shares for cash, securities or other property
subsequent to the Closing Date; or (ix) to the extent required by any legal or regulatory order; provided that in each case of
clauses (i)–(vii), if the transferee is not a Holder, such transferee will agree to be bound by the terms of this Agreement in writing,
in form and substance reasonably satisfactory to PubCo.



(c) Each
Holder also agrees and consents to the entry of stop transfer instructions with PubCo’s transfer agent and registrar against the
Transfer of any Lock-up Shares except in compliance with the foregoing restrictions and to the addition of a legend to such Holder’s
Lock-up Shares describing the foregoing restrictions.



(d) For
the avoidance of doubt, each Holder shall retain all of its rights as a shareholder of PubCo with respect to the Lock-up Shares during
the Lock-up Period, including the right to vote any Lock-up Shares (subject to the other provisions hereof) and any dividends or other
distributions declared on the Lock-up Shares.



(e) During
the Lock-Up Period each certificate evidencing any Lock-up Shares shall be stamped or otherwise imprinted with a legend in substantially
the following form, in addition to any other applicable legends:



“THE SECURITIES REPRESENTED BY
THIS CERTIFICATE ARE SUBJECT TO RESTRICTIONS ON TRANSFER SET FORTH IN A LOCK-UP AGREEMENT, DATED AS OF [_], 2024, BY AND AMONG CRITICAL
METALS CORP. AND THE REGISTERED HOLDER OF THE SECURITIES (OR THE PREDECESSOR IN INTEREST TO THE SECURITIES), AS AMENDED. A COPY OF SUCH
LOCK-UP AGREEMENT WILL BE FURNISHED WITHOUT CHARGE BY THE ISSUER TO THE HOLDER HEREOF UPON WRITTEN REQUEST.”





3







Article
III
Effectiveness



Section 3.01	Effectiveness.
This Agreement shall
become effective on the Closing Date. This Agreement and the obligations of each Party hereunder shall automatically terminateab
initio upon the termination of the Merger Agreement.



Article
IV
Miscellaneous



Section 4.01	Miscellaneous.



(a) Further
Assurances. The Parties shall execute and deliver such additional documents and take such additional actions as the Parties reasonably
may deem to be practical and necessary in order to consummate the transactions contemplated by this Agreement.



(b) Notices.
Any notice or communication required or permitted hereunder shall be in writing and either delivered personally, emailed or sent by overnight
mail via a reputable overnight carrier, and shall be deemed to be given and received (i) when so delivered personally, (ii) when sent,
with no mail undeliverable or other rejection notice, if sent by email, or (iii) the next day when sent by overnight carrier to the address
below or to such other address or addresses as such person may hereafter designate by notice given hereunder:



| | (i) | If to PubCo:
| | --- | ------------



c/o European Lithium Ltd.

32 Harrogate Street

West Leederville, Western Australia,
6007

Attention: Tony Sage

Email: [***]



with copies (which shall not
constitute notice) to:



White & Case LLC

1221 Avenue of the Americas

New York, New York 10020

Attention: James Hu

Email:	[***]



And



White & Case LLP

609 Main Street, Suite 2900

Houston, TX 77002

Attention: Jason Rocha

Email:	[***]



| | (ii) | If to Holder, to the address set forth on Holder’s signature
page hereto.
| | ---- | -------------------------------------------------------------------------





4







(c) Rules
of Construction. Each of the Parties agrees that it has been represented by independent counsel of its choice during the negotiation
and execution of this Agreement and each Party and its counsel cooperated in the drafting and preparation of this Agreement and the documents
referred to herein and, therefore, waive the application of any law, regulation, holding or rule of construction providing that ambiguities
in an agreement or other document will be construed against the Party drafting such agreement or document. The words “hereof,”
“herein,” “hereinafter,” “hereunder,” and “hereto” and words of similar import refer to
this Agreement as a whole and not to any particular section or subsection of this Agreement and reference to a particular section of this
Agreement will include all subsections thereof, unless, in each case, the context otherwise requires. The definitions of the terms herein
shall apply equally to the singular and plural forms of the terms defined. Whenever the context shall require, any pronoun shall include
the corresponding masculine, feminine and neuter forms. Unless otherwise indicated the words “include,” “includes”
and “including” when used herein shall be deemed in each case to be followed by the words “without limitation.”
References to Sections and Exhibits are to sections of, and exhibits to, this Agreement. The Exhibits form part of this Agreement. Any
reference to “writing” or “written” means any method of reproducing words in a legible and non-transitory form.
References to a “company” include any company, corporation or other body corporate wherever and however incorporated or established.
The table of contents and headings are inserted for convenience only and do not affect the construction of this Agreement. Unless the
context otherwise requires, words in the singular include the plural and vice versa and a reference to any gender includes all other genders.
References to any statute or statutory provision include a reference to that statute or statutory provision as amended, consolidated or
replaced from time to time (whether before or after the date of this Agreement) and include any subordinate legislation made under the
relevant statute or statutory provision.



(d) Third
Party Rights. This Agreement is made for the benefit of the Parties and the Permitted Transferees (and their respective successors
and permitted assigns) and is not intended to confer upon any other Person any rights or remedies.



(e) Severance
and Validity. If any provision of this Agreement is or becomes illegal, invalid or unenforceable in any respect under the law of any
jurisdiction, it shall be deemed to be severed from this Agreement. The remaining provisions will remain in full force in that jurisdiction
and all provisions will continue in full force in any other jurisdiction.



(f) Counterparts.
This Agreement may be executed in counterparts and shall be effective when each Party has executed and delivered a counterpart. Each counterpart
shall constitute an original of this Agreement, but all the counterparts shall together constitute one and the same instrument.



(g) Entire
Agreement. This Agreement and the Merger Agreement (to the extent incorporated herein) constitute the entire agreement and understanding
of the Parties with respect to the subject matter hereof and supersede all prior understandings, agreements and representations by or
between the Parties to the extent they relate in any way to the subject matter hereof.



(h) Modifications
and Amendments. This Agreement may be amended or modified by written agreement executed by each of the Parties hereto. The provisions
and terms of this Agreement may only be waived in a writing signed by the Party against whom enforcement of such waiver is sought. No
failure or delay by a Party in exercising any right hereunder shall operate as a waiver thereof.



(i) Assignment.
Except for transfers permitted by Article II, neither this Agreement nor any rights, interests or obligations that may accrue to
the Parties may be transferred or assigned without the prior written consent of each of the other Parties. Any such assignment without
such consent shall be null and void. Subject to the foregoing, this Agreement shall be binding upon, inure to the benefit of and be enforceable
by the Parties and their respective successors and permitted assigns.





5







(j) No
Waiver of Rights, Powers and Remedies. No failure or delay by a Party in exercising any right, power or remedy under this Agreement,
and no course of dealing between the Parties hereto, shall operate as a waiver of any such right, power or remedy of such Party. No single
or partial exercise of any right, power or remedy under this Agreement by a Party, nor any abandonment or discontinuance of steps to enforce
any such right, power or remedy, shall preclude such Party from any other or further exercise thereof or the exercise of any other right,
power or remedy hereunder. The election of any remedy by a Party shall not constitute a waiver of the right of such Party to pursue other
available remedies. No notice to or demand on a Party not expressly required under this Agreement shall entitle the Party receiving such
notice or demand to any other or further notice or demand in similar or other circumstances or constitute a waiver of the rights of the
Party giving such notice or demand to any other or further action in any circumstances without such notice or demand.



(k) Remedies.



(i) The
Parties agree that irreparable damage may occur if this Agreement was not performed and that money damages or other legal remedies may
not be an adequate remedy for any such damage. It is accordingly agreed that the Parties shall be entitled to seek equitable relief, including
in the form of an injunction or injunctions, to prevent breaches or threatened breaches of this Agreement and to enforce specifically
the terms and provisions of this Agreement, without proof of actual damages or the inadequacy of monetary damages as a remedy, in an appropriate
court of competent jurisdiction as set forth in Section 4.01(n) this being in addition to any other remedy to which any Party is
entitled at law or in equity, including money damages. The Parties further agree (i) to waive any requirement for the security or posting
of any bond in connection with any such equitable remedy, (ii) not to assert that a remedy of specific enforcement pursuant to this Section
4.01(k) is unenforceable, invalid, contrary to applicable law or inequitable for any reason, and (iii) to waive any defenses in any
action for specific performance, including the defense that a remedy at law would be adequate.



(ii) The
Parties acknowledge and agree that this Section 4.01(k) is an integral part of the transactions contemplated hereby and without
that right, the Parties would not have entered into this Agreement.



(iii) In
any dispute arising out of or related to this Agreement, or any other agreement, document, instrument or certificate contemplated hereby,
or any transactions contemplated hereby or thereby, the applicable adjudicating body shall award to the prevailing Party, if any, the
costs and attorneys’ fees reasonably incurred by the prevailing Party in connection with the dispute and the enforcement of its
rights under this Agreement or any other agreement, document, instrument or certificate contemplated hereby and, if the adjudicating body
determines a Party to be the prevailing Party under circumstances where the prevailing Party won on some but not all of the claims and
counterclaims, the adjudicating body may award the prevailing Party an appropriate percentage of the costs and attorneys’ fees reasonably
incurred by the prevailing Party in connection with the adjudication and the enforcement of its rights under this Agreement or any other
agreement, document, instrument or certificate contemplated hereby or thereby.



(l) No
Ownership Interest. Nothing contained in this Agreement shall be deemed to vest in PubCo any direct or indirect ownership or incidence
of ownership of or with respect to any Covered Shares.



(m) No
Partnership, Agency or Joint Venture. This Agreement is intended to create a contractual relationship between the Parties, and is
not intended to create, and does not create, any agency, partnership, joint venture or any like relationship between or among the Parties.





6







(n) Governing
Law and Jurisdiction. Each of the Parties irrevocably consents to the exclusive jurisdiction and venue of the state and federal courts
seated in New York County, New York and any appellate court therefrom in connection with any matter based upon or arising out of this
Agreement, agrees that process may be served upon them in any manner authorized by the laws of the State of New York for such Person and
waives and covenants not to assert or plead any objection which they might otherwise have to such manner of service of process. Each Party
and any Person asserting rights as a third-party beneficiary may do so only if he, she or it hereby waives, and shall not assert as a
defense in any legal dispute, that: (i) such Person is not personally subject to the jurisdiction of the above named courts for any reason;
(ii) such Legal Proceeding may not be brought or is not maintainable in such court; (iii) such Person’s property is exempt or immune
from execution; (iv) such Legal Proceeding is brought in an inconvenient forum; or (v) the venue of such Legal Proceeding is improper.
Each Party and any Person asserting rights as a third-party beneficiary hereby agrees not to commence or prosecute any such action, claim,
cause of action or suit other than before one of the above-named courts, nor to make any motion or take any other action seeking or intending
to cause the transfer or removal of any such action, claim, cause of action or suit to any court other than one of the above-named courts,
whether on the grounds of inconvenient forum or otherwise. Each Party hereby consents to service of process in any such proceeding in
any manner permitted by New York law, and further consents to service of process by nationally recognized overnight courier service guaranteeing
overnight delivery, or by registered or certified mail, return receipt requested, at its address specified pursuant to Section 4.01(b).
Notwithstanding the foregoing in this Section 4.01(n), any Party may commence any action, claim, cause of action or suit in a court
other than the above-named courts solely for the purpose of enforcing an order or judgment issued by one of the above-named courts.



(o) No
Recourse. Notwithstanding anything to the contrary contained herein or otherwise, but without limiting any provision in the Merger
Agreement or any other transaction document, this Agreement may only be enforced against, and any claims or causes of action that may
be based upon, arise out of or relate to this Agreement, or the negotiation, execution or performance of this Agreement or the transactions
contemplated hereby, may only be made against the entities and Persons that are expressly identified as parties to this Agreement in their
capacities as such and no former, current or future shareholders, equity holders, controlling persons, directors, officers, employees,
general or limited partners, members, managers, agents or affiliates of any Party, or any former, current or future direct or indirect
shareholder, equity holder, controlling person, director, officer, employee, general or limited partner, member, manager, agent or affiliate
of any of the foregoing (each, a “Non-Recourse Party”) shall have any liability for any obligations or liabilities
of the Parties or for any claim (whether in tort, contract or otherwise) based on, in respect of, or by reason of, the transactions contemplated
hereby or in respect of any oral representations made or alleged to be made in connection herewith. Without limiting the rights of any
Party against the other Parties, in no event shall any Party or any of its affiliates seek to enforce this Agreement against, make any
claims for breach of this Agreement against, or seek to recover monetary damages from, any Non-Recourse Party.



[Signature Page Follows]



7







IN WITNESS WHEREOF,
the Parties have executed or caused this Lock-up Agreement to be executed by its duly authorized representative as of the date set forth
below.



PUBCO:



Critical Metals Corp.



|By:    |                     | 
|------ | ------------------- | 
|Name:  | Michael John Hanson | 
|Title: | Authorized Person   | 





8







IN WITNESS WHEREOF,
the parties hereto have caused this Lock-up Agreement to be duly executed by their respective authorized signatories as of the date first
indicated above.



Holder:



Name of Holder: [_______________________________]



|By:    |  | 
|------ |  | 
|Name:  |  | 
|Title: |  | 



Number of Lock-Up Shares::______________________________________________



Address for Notice:



|Address:_____________________________________  | 
|---------------------------------------------- | 
|                                               | 
|____________________________________________   | 
|                                               | 
|____________________________________________   | 
|                                               | 
|Facsimile No.:________________________________ | 
|                                               | 
|Telephone No.:_______________________________  | 
|                                               | 
|Email:______________________________________   | 





9