In the third series of Skins, O'Connell's Cook kissed Pasqualino's Freddie during a fight over Effy (Kaya Scodelario).
Speaking to Gay Times, Pasqualino said that he "didn't really know it was going to happen".
Recalling the plot, he said: "Freddie and Cook have had this relationship since they were little; they've always competed - who could run the fastest, who was best at football - and now they're competing for this girl.
"When Freddie headbutts Cook, Cook half admits that he deserves it so instead of going mad and hitting him back he grabs him and kisses him, to say: 'You're a prick for hitting me... but I deserved it, and I still love you'."
He continued: "I didn't really know it was going to happen - well, I kind of half knew. I don't know if I didn't read the script properly or if the directors had said to Jack: 'We're not going to do this in rehearsal'.
"But the whole thing was meant to look like it took Freddie by surprise. And it did!"
Skins returns for its fourth series Thursday at 10pm on E4.