Colin Firth "relished making a fool" out of himself when filming 'Mamma Mia'.
What on earth were we doing? Committing career suicide? That audiences liked it was very gratifying
The British actor appeared alongside other A-list stars including Pierce Brosnan and Meryl Streep in the romantic musical film - based on the songs of Swedish pop group ABBA - and said he enjoyed making it because none of them ever took it too seriously.
He told website nj.com: "I think dignity can be a little overrated. I just relished making a fool of myself, really, along with all these rather serious actors.
"There was a fantastic kind of recklessness to it; every time we finished a take, we would look at each other and blanch. What on earth were we doing? Committing career suicide? That audiences liked it was very gratifying. Really, it's one of the experiences I regret least in my life."
Colin - who has starred in blockbusters including 'Bridget Jones's Diary', 'Love Actually' and 'The English Patient' - added, however, that in other projects, if the chemistry isn't there between the stars, they can become a "misery" to make.
He added: "It can be utter misery. Because you are trying to manufacture something that's supposed to be happening naturally.
And I think everyone knows what that's like, in some area of life. You can't make things like that happen. And I'll tell you, if the other people involved in the project are not that good, it doesn't make you look any better. It's quite the reverse, actually. You look your best when you're working with someone better than you."
Colin stars in 'The King's Speech' which is released from December worldwide.