'Anna Karenina': Keira Knightley Says Playing Elizabeth Bennet Was 'More Terrifying' (PICTURES)

Hollywood star Keira Knightley says that she found stepping into Elizabeth Bennet's shoes far more intimidating than playing her latest alter-ego, Anna Karenina.

The actress, 27, plays the protagonist in writer Tom Stoppard's new adaptation of Leo Tolstoy's epic, Russian love story.

But she said playing the heroine in the big-screen adaptation of Jane Austen's novel Pride And Prejudice, the 2005 film which was also directed by Joe Wright, was daunting.

Keira Knightley as Anna Karenina

"Playing someone like Elizabeth Bennet is more terrifying because it's a character that people love, a lot of women ... see themselves as," she said.

"People don't see themselves as Anna. They don't have this love for her ... from that point of view, it's not as terrifying".

Keira said that views about marriage had changed since the publication of Tolstoy's novel, set in Imperial Russia.

"I think what it's morally saying is that you shouldn't do what Anna does, you shouldn't leave your husband, you shouldn't cheat."

Keira Knightley as Anna Karenina

But the actress, who is engaged to her rocker boyfriend James Righton, added at a press conference: "The idea of not leaving an unhappy relationship, is not something I agree with. I think you should get out if you need to get out."

Jude Law plays Anna's husband Karenin in the film, while Aaron Taylor-Johnson is Vronsky, her lover.

The film, which opens in cinemas on September 7 2012, has its world premiere in London on Tuesday night.

See Keira's style through the years!