The film explores the dark side of fame, fortune, and celebrity, something Firth says he was immediately attracted to.
"I liked all the dark stuff, the unpredictability of the character, and I thought it had a lot of possibilities," he told the BBC News website.
"[Darker roles] are not entirely new to me. In Trauma, which I did about three years ago, and throughout the 1980s, I was playing characters who were less than pleasant."It's not a reaction to typecasting - I just tend to like that territory. "I have reaped enormous benefits from doing rom coms... but I tend to be more comfortable in drama than in comedy."
Tortured is always good for an actor. I don't know anyone who doesn't want to do a bit of torturing," he added.
"It is hard to imagine any central character in any film that is happy at the beginning, happy in the middle, then happy at the end. What story has there been?....more
