For Firth, who still struggles to break away from the image of charming Mr Darcy, the role in BBC's TV adaptation of Jane Austen's 'Pride And Prejudice' brought him fame 15 year ago, taking up the role was a challenge, News of the World reported.
The actor is playing an academic coming to terms with his boyfriend's death in California in 1962 - when being gay was not okay. Firth said he has several nude scenes in the movie, which in part inspired him to sign the film.
"I pick up the script and it says, 'Naked man lies on bed.' And then a few pages in, 'Naked man jumps in ocean.' 'Well,' I thought. 'It's time. One more push against gravity before I turn 50 and it's all downhill," Firth said.
The 'Bridget Jones' star has already got a Bafta Best Actor gong under his belt and is now looking forward to win the Oscar, where he has been pitted against George Clooney, Morgan Freeman, Jeff Bridges and 'The Hurt Locker' Jeremy Renner.
"I'm not very hopeful, I'm afraid. It's just nice to get the nomination. "I think it was one in five before (the Bafta) and I think it's probably one in five now - at best. The competition is pretty terrifying, quite frankly," Firth said.