Keira Knightley faces her toughest screen challenge to date as the tragic titular figure in Anna Karenina, which is in cinemas now. The newly engaged actress reveals her thoughts on love, how she had her male co-stars quaking in their boots and why she doesn't care if she's loved or not on film.

By Susan Griffin

She's one of the most famous women in the world but it's no secret Keira Knightley detests any form of inquiry into her private life.

It's brilliantly demonstrated by the steely look that flashes across her doe-like eyes at the mention of her engagement to James Righton.

He's the 29-year-old Klaxons keyboardist she met through mutual friend Alexa Chung, following failed long-term romances with model James Dornan and actor Rupert Friend.

The reference may only be to congratulate her on her forthcoming nuptials but it's enough for the 27-year-old to close imaginary shutters - with a bang.

But it's only momentary.

Asked if she thinks she's learnt anything about love from starring in Leo Tolstoy's sweeping romance, Anna Karenina and the famous pout breaks into a wide grin.

"God no!" she says. "Far too bleak, no, better to ignore the whole thing I think."

In Anna Karenina, Knightley plays the titular young wife who scandalises 19th century Russian society by abandoning her dull but powerful husband Karenin, played by a balding and bespectacled Jude Law, for the dashing Count Vronsky, depicted by Aaron Taylor-Johnson.

It marks her third collaboration with the filmmaker Joe Wright, the man who famously banned the actress from pouting on screen.

In 2005 he directed her to an Oscar nomination as Elizabeth Bennet in Pride & Prejudice and two years later to a BAFTA nomination in the World War Two romance Atonement.

In tackling the doomed protagonist, Knightley is showing the world that the tomboy who delighted audiences in Bend It Like Beckham a decade ago is now cementing her status as an accomplished and versatile actress.

And Anna Karenina is indeed one heck of a part, one that's previously been played by such acting greats as Vivien Leigh and Greta Garbo.

Knightley herself has referred to the role as the female equivalent of Hamlet.

"I'm not sure I'm right about that," she says today.

"What I meant was she's a huge female role and one that's very difficult for any actress to turn down.

"You're never sure whether the purpose of Anna is to be the heroine or anti-heroine."

Daughter of actor Will Knightley and playwright Sharman McDonald, the Richmond-born actress speaks in a rat-a-tat pattern, sounding incredibly posh as the words tumble out one after the other.

Off-duty she's known for her casual, grungy look but today, in promotional mode, the slight actress is wearing a green designer dress with capped sleeves that unfortunately "keeps riding up", she divulges.

As part of her preparation, Knightley re-read the novel she'd first encountered in her late teens and found her own feelings towards the character and story had evolved.

"I remembered the book as being just incredibly romantic with this extraordinary character but in re-reading the novel I suddenly went, 'Oh my God, this is dark'," says Knightley.

She recalls lengthy discussions with Wright and screenwriter Tom Stoppard about Anna's complexities.

"I think she's this strange, jewel-like creature and we were constantly questioning ourselves abut how far we could take the manipulative, destructive side of her before she turns into someone who's repellent. It was a constant juggling act."

It's why she says her copy of the novel was heavily marked with a myriad amount of coloured post-it notes.

"I'm very into stationery," she jokes.

"I think I frightened all the boys because they could see the homework I'd done with these colourful post-it notes. It terrified them."

Her fear of simplifying the multifaceted Anna meant she immersed herself in the character to a point that she couldn't always shrug her off at the end of the day.

"She did definitely come home on a couple of occasions and I don't think I was the easiest person to live with when I was playing her," reveals Knightley.

"But that's part of the experience of playing a character like that."

Having said that, she doesn't believe Anna to be the toughest role she's undertaken.

"Someone like Elizabeth Bennet is more terrifying because it's a character that people love," says Knightley.

"They fall in love with her and they see themselves as her.

"People don't see themselves as Anna. They see her as this strange creature so, from that point of view, it's not as terrifying.

"But there's always a responsibility, particularly when it's a story that's been done so many times," she insists.

Unlike other adaptations, Wright has eschewed the typical epic locations and relocated the action to a decaying but beautiful theatre.

But it's not such a radical move given the Russian society of this time was suffering something of an identity crisis.

Not knowing whether they were part of the East or the West, the Russians took matters into their own hands and chose to be cultured like the French.

They followed French fashion, read books on French etiquette and their ballrooms were often mirrored so they could appreciate their own 'performances' just as French society did.

Knightley says: "You had a whole society who were pretending to be something they weren't, all the time."

It only emphasises the levels of hypocrisy present when Anna is shunned by her peers following the revelation of her affair.

But that's not something exclusive to early Russian society.

"I think societies are full of hypocrisy, always," says Knightley.

"And anyone who stands morally over anyone else is probably being a bit hypocritical. I haven't met anybody who has the right to judge anyone else.

"And yet we all do it all the time, so I think we live with hypocrisy on a day-to-day basis."

She doesn't think Anna deserves to be held up as morally corrupt either.

"The story is one we understand today because people still want something they cannot have, still come up against social blocks and rules, and still have trouble communicating emotions to each other," she says.

"I don't think you can stand in judgement over the fact that she gets caught up in this thing [affair].

"When you look at it and you look at your own life and your own emotions and your own failings perhaps, I wonder whether we'd do anything different?"

Particularly given our modern sensibilities, she adds.

"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."

On a lighter note, she found the dancing required of her in the vital ballroom scene, in her own words, "a nightmare".

"I think I'm quite quick at picking things up like that but actually I did find this impossible," she says, laughing. "I'm not a dancer so it was really tricky."

She's not a singer either but says "I gave it my best shot" in her next venture Can A Song Save Your Life? which she recently wrapped in New York.

"Anna Karenina was such an incredibly intense, wonderful experience but it's incredibly dark and the depths that Anna goes to was quite tiring," says Knightley.

"So I went away to New York and did this incredibly positive film."

Extra time - Anna Karenina

:: The script was already written when Joe Wright made the bold decision to set the story in a theatre, which was built at Shepperton Studios.

:: 1,500 Russians turned up to be cast as extras after an advert appeared in Russian speaking newspaper.

:: Costume designer Jacqueline Durran who also worked on Pride & Prejudice and Atonement was given a brief for the costumes be in the style of 1950s couture, but the silhouettes of the 1870s.

:: A small unit travelled to Russia in February for a few days to shoot some of the film's few exterior scenes on a remote island near Lake Onega.

:: Anna Karenina is in cinemas now