The Brit admits he didn't know what to do with himself when he became an overnight sensation - and his castmates Kristen Stewart and Taylor Lautner took off to make other films.
He tells Premiere magazine, "I went through a big time of depression between 23 and 25, I couldn't go where I wanted to go, I was in the tabloids every day and I didn't have access to the roles I really wanted. I wanted more, on every level.
"I finally realised that you needed to earn this change I so desperately wanted. That one way or another, you had to suffer to be able to make it. I thought everything was going to be served on a plate but that's not how it works.
"When (director) David Cronenberg offered Cosmopolis to me, I never read anything as interesting for years. I saw Kristen leave to film Snow White and the Huntsman, Taylor was also doing his thing on the side, and I was just going in circles, asking myself if I was going to take a break and go back to music. Then one day David called and I went crazy."