Guess Who (waxaa lagu habeeyay dhammaan safka ama sida GUE?? WHO) waa EP-ka afaraad ee dheerayd ee ay sameeyeen kooxda gabdhaha Itzy.  Waxaa sii daayay JYP Entertainment Abriil 30, 2021. EP-ka waxaa loo sii daayay horay-u-dalbashada Maarso 22. EP -ku wuxuu ka kooban yahay lix waddo, oo ay ku jiraan kuwa keli ah "In the Morning". EP wuxuu ka helay guulo ganacsi iyo guud ahaan dib u eegisyo wanaagsan dhaleeceeyayaasha muusikada, kuwaas oo bogaadiyay nooca muusigga hip hop ee lagu soo bandhigay albumka; si kastaba ha ahaatee, xoogaa dhaleeceeyayaal ah ayaa helay maaddadii xakamaynaysay muhiimadda kooxda.  Waxay ku calaamadeysay Itzy gali ​​ugu horreeyay uguna sarreeyay Gobolada Isku Tegay ee Ameerika Billboard 200, lambarka 148, iyo lambarka 2 ee Shaxda Albumka Gaon. Bishii Maajo 2021, Guess Who ayaa shahaado ka siiyay Platinum Ururka Macluumaadka Muusikada Kuuriya. "ITZY debuts on Billboard 200 with new album 'Guess Who' - The Korea Herald".