"It's definitely a lot of fun," Styles told ET on the carpet. "I've already done the work part, so this is definitely the fun bit. We're all super proud of the film, so this is definitely the exciting bit for us."
"As a director, I have to trust my instincts, my ability to figure out who's the right guy for the part," Nolan said. "What I was seeing [when he auditioned] was a very charismatic guy who clearly had a truthfulness and a subtlety in his ability to perform as a film actor."
"When I cast Heath Ledger as the Joker [in The Dark Knight], it raised a lot of eyebrows and caused a lot of comment," he added. "I have to trust my instincts, and Harry was perfect for this part." Check out the video below to hear more.