It was the jujutsu sorcerers break, meaning they could have small plans. Fushiguro, who really loved tv girl(ofc), booked tickets for the concert of, "Lovers Rock". He went to Itadori because he had an extra ticket, and sometimes they listen to tv girl together. he asked,

“Itadori… can you dress in pink for the tv girl concert tomorrow..? i’m gonna wear blue ..”

Itadori: “of course!” he said, a bright smile on his face. today is the day of the concert.