Attempting to woo his beloved in The Importance of Being Earnest — opening Friday — Colin Firth's character serenades her. Of course, we're dying to know: Was the handsome Brit crooning with his own voice in the film?

"I'm very flattered that you even ask [if it was me]," Firth tells TV Guide Online. "If they got a professional voice in [instead], it would have sounded a lot better than that.

"I didn't really prepare very much except in my bedroom once or twice," the 41-year-old adds. "It was a fairly unprepared thing, but I think that was the spirit that was required. I was rather hoping it would all be dubbed!"

Firth has a very different opinion when it comes to the vocal performance of co-star Reese Witherspoon — whose part calls for her to utter Oscar Wilde's witticisms with a British accent. "I certainly think that nobody could have been better in the role," he gushes. "We all had to make a bit of a reach... No one speaks like that. [The play]'s a hundred years old and most of us English people are fairly detached from that culture and that way of speaking now."

It's one thing for Brits to return to their roots, but can an American do it as well? "I think that the nationality and the origins of the person really come second," he asserts. "I'd rather she even got the accent wrong than have a perfect English rose who can't act."

In fact, Firth has a happy track record of acting opposite U.S. starlets playing UK beauties. Besides Witherspoon, he's also co-starred with Renée Zellweger in Bridget Jones's Diary and Gwyneth Paltrow in Shakespeare in Love. "Every time an American actress has come to do a film in England, I've usually been there in the film as well," he laughs. "So, I've always heard all the talk. But I don't know if there's really been a fuss about it. It may be more of a problem [in the States] than it is in England. We don't particularly care."