December 23, 1996
Page 1


                                                                   Exhibit 10.66

                                December 23, 1996


Ladies and Gentlemen:

         This  letter  agreement  (the  "Agreement")  is being  entered  into in
connection  with the  execution of an Agreement  and Plan of Merger (the "Merger
Agreement"),  dated as of December 23, 1996, among GemStar  International  Group
Limited ("GemStar"),  G/S Acquisition Subsidiary ("Sub") and StarSight Telecast,
Inc. (the "Company"), pursuant to which, among other things, Sub will merge with
and into the Company (the  "Merger"),  subject to the terms and  conditions  set
forth in the Merger Agreement.  Capitalized terms which are used but not defined
herein shall have the meanings ascribed to such terms in the Merger Agreement.

         The purpose of this  Agreement is to confirm our mutual  understandings
and agreements with regard to the Employment  Agreement  between the Company and
Brian L.  Klosterman  (the  "Executive"),  dated as of  December  21,  1995 (the
"Employment  Agreement"),  as it  relates  to the  Executive.  The  Company  has
requested  that,  for  the  benefit  of  its  shareholders  (which  will  become
shareholders of GemStar after  consummation of the Merger),  the Executive enter
into this Agreement.

         The Company agrees to pay on the Payment Date, and the Executive agrees
to accept payment of $350,000 (the "Total Accelerated Payments").  Such payments
shall  be  treated  for  tax  withholding  and  reporting  purposes  as  taxable
compensation to the Executive as of the Payment Date.

         The  Executive  agrees,  on his  behalf  and on  behalf  of his  heirs,
assigns,  executors,  administrators  and legal  representatives,  that upon the
Executive's  receipt of such payments,  the total amounts  payable (or that will
become  payable)  under the  Employment  Agreement  will be reduced by the Total
Accelerated  Payments.  The Company and the Executive  agree that the receipt by
the Executive of the Total Accelerated Payment shall be without prejudice to any
other  provision of the Employment  Agreement,  including,  without  limitation,
rights to  payments  due to the  Executive  (other  than the  Total  Accelerated
Payments),  the acceleration of Executive's options pursuant to Section 2 (e) of
the Employment  Agreement and rights to continued  employee benefits pursuant to
Section 2(d) of the  Employment  Agreement,  and that nothing in this  Agreement
shall have any effect  whatsoever on the rights of the Executive to receive from
the Company  reimbursement with respect to taxes as set forth in Section 5(b) of
the Employment Agreement.


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December 23, 1996
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         In the event that after payment of the Total  Accelerated  Payments the
Merger is not  consummated  pursuant  to the  Merger  Agreement  and the  Merger
Agreement is terminated (for any reason), then:

         (1)      the Company shall notify the Executive of:

                  (a)      the termination of the Merger Agreement,

                  (b)      the amount of the Total Accelerated Payments that was
                           withheld by the  Company to pay taxes (the  "Withheld
                           Amount"), and

                  (c)      the amount of the Total Accelerated Payments that was
                           actually paid to the  Executive,  net of the Withheld
                           Amount (the "Received Amount");

         (2) the Executive  shall,  within five business days of receipt of such
notice,  notify the Company of any taxes (other than the  Withheld  Amount) that
have been paid by the Executive with respect to the Total  Accelerated  Payments
or that the  Executive  reasonably  expects  to pay with  respect  to the  Total
Accelerated Payments (the "Excess Tax Amount");

         (3) the Executive shall, within five business days after receipt of the
Company's  notice,  reimburse the Company for the excess of the Received  Amount
over the Excess Tax Amount; and

         (4) the  Company  and the  Executive  shall use  reasonable  efforts in
seeking any available  refund or reduction in tax liability  with respect to the
Withheld Amount or the Excess Tax Amount,  as the case may be; in the event that
the  Executive  receives  a refund  from any  taxing  authority  or  realizes  a
reduction to the  Executive's  tax liability with respect to the Withheld Amount
or the Excess Tax Amount,  the Executive shall promptly reimburse the Company in
the amount of the refund or reduction in tax liability,  as  applicable,  net of
any taxes imposed  thereon,  and in any event not to exceed the aggregate amount
paid by the Company to the Executive hereunder.

         Whether  or not the  Merger  is  consummated,  in the  event  that  the
Executive  becomes  liable for any taxes  (including,  without  limitation,  any
interest or penalties  imposed with respect to such taxes or acceleration of the
timing of the  Executive's  payment  of any such  liability)  as a result of the
Total Accelerated Payments being paid hereunder that would not have been payable
had such payments been made immediately after the consummation of the Merger, or
as a result of any payment made by the Executive to the Company pursuant to this
Agreement (in any such case, an "Executive  Tax  Liability"),  the Company shall
indemnify the Executive on an after-tax  basis so as to make the Executive whole
with respect to any such Executive Tax Liability.

         In  addition,  whether or not the Merger is  consummated,  the  Company
shall  indemnify the  Executive  for  reasonable  expenses  (including,  without
limitation,  reasonable  attorneys',   accountants'  and  expert  witness  fees)
incurred in connection with any action, suit, claim, liability or proceeding (a


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December 23, 1996
Page 3


"Claim") arising by reason of this Agreement, including, without limitation, any
audit or other proceeding relating to the defense of an Executive Tax Liability,
and any and all  Claims  of the  Company  or third  parties  (including  without
limitation  any Claims  against  which the  Company  would not be  permitted  to
indemnify the Executive).  The Company shall make any payments required pursuant
to this  Agreement  (other than the  Withheld  Amount and the Excess Tax Amount,
which  shall be made as set forth  above)  within  five days  after it  receives
written  notice that any expense,  judgment,  fine,  settlement or other amount,
including,  without limitation, a Tax Liability or related expense, actually has
been incurred.

         Except as  expressly  set forth  herein,  this  Agreement  shall not be
deemed to affect or modify any provision of the Employment Agreement.

         This  Agreement  may not be amended  or  terminated  without  the prior
written consent of the Company and the Executive.

         This  Agreement  may be  executed in any number of  counterparts  which
together shall constitute but one agreement.

         This  Agreement  may not be assigned  by any party  hereto and shall be
binding on and inure to the benefit of their  respective  successors and, in the
case of the Executive, heirs and other legal representatives.




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December 23, 1996
Page 4

         The Company and the  Executive  have caused this  Agreement  to be duly
executed as of the date first above written.


                                             STARSIGHT TELECAST, INC.

                                             By:    /s/  Larry W. Wangberg
                                                   _____________________________
                                             Name:       Larry W. Wangberg
                                             Title:      Chief Executive Officer



                                                  /s/ Brian L. Klosterman
                                             ___________________________________
                                                      Brian L. Klosterman