For Keira Knightley, playing Anna Karenina was the mirror image of playing Jane Austen's Elizabeth Bennett. As the heroine of "Pride and Prejudice," Knightley played a heroine beloved by generations of readers. Starring in Tolstoy's drama of infidelity, vengeance and retribution, she had to walk an emotional tightrope, making her adulterous character spirited, energetic, relatable, yet not too likable. Knightley feared that if she made Anna an innocent victim, "you're going to lose the audience, and if you lose the audience they are just going to go, 'Oh, shut up and jump under a train!'"

"There are moments when Tolstoy hates her," she said. "I first read the book in my late teens and remembered it as this sweeping romance. Then I went back to it last summer and thought, 'This is a very different thing than I remembered.' Sometimes she is the anti-heroine. He's almost holding her up and saying, 'This is the Whore of Babylon.' He's not going, 'You should go off for this romantic love.' Then sometimes you feel he completely understands her and he's absolutely in love with her."

Director Joe Wright wanted all those contradictions, Knightley said.

"That's the dichotomy of Anna that has made her such a fascination for so many years," Knightley said.

When half the financing dropped away, Wright's conception of the film changed radically. What was envisioned as a naturalistic production shot in Russia quickly became a stylized, mostly soundstage version. The shift is well-suited to a story of a society where false and artificial values were paramount.

Wright's theatrical staging provides an ingenious background for Knightley's tortured passions, with Jude Law superb as her fussy, cold husband, Alexi, and Aaron Taylor-Johnson's romantic Vronsky the most dashing fellow since Errol Flynn swung from his last chandelier.

Knightley and Taylor-Johnson spent a fair amount of time stumbling into each other as they practiced their big ballroom dance scene.

"It's different rehearsing something in track-suit bottoms and suddenly adding a dress that was so heavy it felt as if I had a small child attached to my waist," she said. "All of a sudden you're twirling around and someone behind you is stepping on the back of your skirt, and then he steps on the front and I can't see my feet and I'm stepping on his.

"It was annoying because he picked up the dance like that, and it took me about three weeks."

Although she's no stranger to costume drama (or comedy, if you count her "Pirates of the Caribbean" films), Knightley never had a wardrobe to match Anna's. As a socialite in 19th-century St. Petersburg, Anna dresses in the height of fashion, luxury and vanity.

Costume designer Jacqueline Durran (who also costumed Knightley in period style for Wright's "Pride and Prejudice" and "Atonement") visited Chanel in Paris to borrow yards upon yards of pearls and bushels of diamonds. Each morning Knightley would choose what kind of jewels she wanted from a treasure chest worth about $2 million.

Her wardrobe helps tell the story, too.

"The themes of Anna that we liked and that made a lot of sense to me was this idea that she's a bird that's stuck in a cage," Knightley said. "Her hoop skirt frame is the cage; the veils are these beautiful cages. The idea is that it's claustrophobic, she's caught, so she's constantly surrounded by death in the furs.

"She's got these birds that can't fly stuck to her head. The diamonds are very harsh kind of stones. The only time that we ever brought a color into the jewelry was when we had a ruby that is blood red."

While she admitted some misgivings about the film's sudden shift in style, Knightley said she never doubted Wright's "complete obsession" with making an "Anna Karenina" that stands apart from the many earlier adaptations.

"I'm incredibly proud of it. If you think of cinema as an event, it certainly is an event. You'll only ever see naturalism on film at the moment and whether you think it's overstylized or not, you just have to celebrate the fact that it's just so completely different," she said.

"I love it, and how daring Joe has been. I'm glad I jumped off the cliff with him."

Colin Covert • 612-673-7186