Frances O'Connor has played her share of classic roles, from Maggie Pollitt in the London stage production of Cat on a Hot Tin Roof to Gwendolen Fairfax in the latest film version of Oscar Wilde's The Importance of Being Earnest (opening tomorrow). Yet, the 32-year-old actress admits she still gets nervous tackling well-known characters.

"I always feel at the start, 'Oh god, I've got to get this right,'" she tells TV Guide Online. "But as you work on it, you get drawn into it and you become interested in it creatively. [You begin to think], 'What can I do to make this interesting?'"

However, O'Connor says she doesn't over-analyze every part she plays. "There are some jobs that I like that are fun jobs, like [the upcoming Michael Crichton thriller] Timeline," she confesses. "And then there are other jobs, where it's really about the art and the work — [like] A.I. Artificial Intelligence — where you really want to come up with something interesting."

Incidentally, Earnest proved to be a technical challenge as well for the Australian-bred thesp. In fact, one of her most difficult scenes involved her driving an old-fashioned car. "It was a real antique car and it's done by pedals," she explains. "It's slightly complicated, actually. And at one point, I couldn't stop the car and it kept going. I almost crashed into the crew!"