Joaquin Phoenix struggled to perform his character Joker's mad cackle on the set of the movie. The actor, who portrays the DC Comics supervillain in the new origin tale, had a hard time perfecting the mad laugh, which frames his eccentric character.
"There were some scenes where, for whatever reason, it came out and it felt right and other scenes that it was a struggle," he recalled to ET Online. "Sometimes one take would work and another wouldn't. I think it was something that was alive, in a way."
Nailing the evil laugh was an issue for Joaquin from day one, with the star explaining he was unsure if he could do it even after he landed the role in director Todd Phillips' film.
"I had the part, but I felt like I needed to audition the laugh because I didn't know if I had it or not," he detailed. "I asked Todd to come over to my house to audition the laugh, and he said that wasn't necessary. I said it was. It was very important that I was able to do it in front of him whenever I needed to."
As the film shoot progressed, Joaquin continuously failed to hit the mark on Joker's crazed laugh - brought on by neurological damage that causes sudden bouts of "uncontrollable laughter". "I thought at some point that it would become easier, but I don't think it did," he shared. "I think it became more difficult, actually."
Joker hits U.S. theatres today.