"None of us pretended we were good singers or dancers," said Cooper, who grew up in Greenwich, England, and honed his craft at the London Academy of Music and Dramatic Art. "We were totally unequipped. You could see that look of fear, but we had to embrace it and go for it.

"I thought my singing and dancing were hateful," he jokes.

Despite Cooper's disclaimer that he can't sing, he does acknowledge a love of music and his own interpretation of ABBA.

"I had this secret desire to be a rock star," Cooper says. "... I had a girlfriend then who pushed me into wearing a fur coat, and there's a video of me singing an entire track of 'Money, Money, Money' in a fur coat when I was 13."

Although Sky is a small part, Cooper's time on the screen is memorable. With his dark hair and good looks, he's drawn comparisons to Firth.

"He jokes that he hates my being tabbed the next Colin Firth," Cooper says. "I get along really well with Colin. He has a very dry sense of humor, and I have a long way to go to be like him."

Cooper doesn't want to be known as that brooding guy, and he has already gone against type in some forthcoming films. For a BBC production of "God on Trial," about Jewish inmates at Auschwitz who question God, Cooper shaved his head. And he's very proud of "The Escapist," co-starring Brian Cox and Joseph Fiennes, in which Cooper plays a convict who is part of a prison escape plan.

"It was shot in 26 days," he says. "So rushed and so brilliant."

Cooper's enthusiasm is evident in everything he talks about. He has fond memories of all of his work — and especially of "Mamma Mia!"

"Being six weeks on a Greek island and working with all these people was incredible. I felt we were part of something truly special. After we got over the barriers of making great fools of ourselves, it was more fun than anything else. Everyone who collaborated on it was wonderful. We're all part of the outcome. I think we proved ourselves."