At 29, there's still something of the little girl about Natalie Portman.
It's not that she lacks adult roles. Her last film, Jim Sheridan's Iraq drama Brothers, saw her play an emotionally torn war widow. Before that, she was an Oscar-nominated stripper in Closer and a chronic gambler in My Blueberry Nights. Maybe it's her appearance, then. Her skin is still enviably fresh, today coloured with a little blusher, and her cigarette-slim 5ft 3in frame still has the flush of youth about it. And her midnight-blue dress, with its high neckline and knee-length hem, is the sort of respectable garment your parents might pick out for you.
Or more likely, it's that I've just seen Portman in Black Swan at the London Film Festival She plays Nina, a virginal New York ballerina who still lives with her suffocating mother (a brilliant Barbara Hershey). Her room is pink and filled with fluffy toys. And she's innocent when it comes to the wicked ways of her ballet company's lascivious artistic director (Vincent Cassel), who casts her as the Swan Queen in a new production of Swan Lake. "It was definitely going back to being a girl," Portman comments. "Though she does become a woman during it."
What makes Black Swan so fascinating, however, is how Portman and director Darren Aronofsky place Nina's sexual awakening in the realms of psychological horror as she becomes increasingly pressurised to seek out her darker side for the sake of her role. Influenced by the early work of both David Cronenberg and Roman Polanski (Mia Farrow's mental disintegration in Rosemary's Baby is particularly key), it all adds up to one of the most original films of the year. And for Portman? She calls it "the most challenging and the most rewarding" role of her career. For once, this is no Hollywood hype.
So convincing is she, Portman has already won a Golden Globe and remains the bookmakers' favourite to win her first Best Actress Oscar. It's not just the fact she essays a young girl's coming-of-age so well. It's that, in a film that has transformation as its core theme, Portman spent a gruelling year training, toning and tooling her body to become like a ballerina's. A vegan by nature, she even dropped 20lbs -- what she calls "the starvation part" of her preparation -- in the final month before the shoot began.
If her weight loss is not as dramatic as, say, Christian Bale's in The Machinist, you have to consider that Bale wasn't training to dance for his role. It all culminated in the most rigorous shoot of her life -- six-day weeks, 16 hours a day. "There were a few days where I thought I might die, literally," she smiles, before admitting she's being a little over-dramatic. Yet the pain was excruciating at times, particularly when she dislocated a rib. "If I was touched there it literally felt like I was being stabbed," she explains. "But it's nothing to complain about. All of the dancers are always dancing with an extreme injury."
Nevertheless, for a film that deals with obsession and the need for perfection, it feels wholly apt that Portman should put herself through such trials. "I'm very demanding with myself," she says. "I like discipline. I like order and regiment. I'm a soldier! And it was amazing to have Darren in the war with me. We're very similar in our extremism."
While Aronofsky calls her "responsible, reasonable and sane", it's an enduring self-image, the petite Portman viewing herself as one who goes into battle. How come? "I just enjoy the discipline," she shrugs. "By nature, I'm more of an obedient person than a rebellious one -- but I'm trying to work on that!"
She says she differs from the rigid Nina in one distinct way. "I'm a pleasure seeker. Usually, I can't starve myself. I can't cause myself pain. I'm the opposite of that. I get acupuncture. I go swimming. I like to cook. I like hanging out with my friends. When I'm not working, I need those days where I just stare at the wall for a few hours and refresh by doing absolutely nothing."
Still, it's interesting that Portman -- who admits she's "only starting to shake off" the role now -- is engaged to and pregnant by Benjamin Millepied, her Black Swan choreographer. While past loves include Mexican actor Gael García Bernal and American folk singer Devendra Banhart, romancing the man who put you through all that pain hardly seems like a way to let go.
In many ways, Black Swan brings the Jerusalem-born Portman full circle. When she was four, just one year after her family (her father is Israeli, her mother American) moved to the US, she started dance lessons. Like most little girls, she fantasised about being a ballerina. "I definitely had that aspiration when I was younger, which was quickly replaced with wanting to be an actress when I was 12. That's when I stopped dancing." Even then, Portman -- an only child -- had a laser-like focus. She refused the opportunity to become a child model for Revlon when she was 10, so she could concentrate on her acting. "I was a very serious kid," she says.
Fortunately, Hollywood took her seriously. She made a huge impact in her debut Leon as Mathilde, the young girl who befriends Jean Reno's monosyllabic hitman. Then, in a run few actors could ever compete with, she worked with Michael Mann (Heat), Woody Allen (Everyone Says I Love You), Tim Burton (Mars Attacks!) and George Lucas (The Phantom Menace). "I don't need the prestige of a big part," she says. "Just the experience of working with anyone like that is enough for me." Yet rather than capitalise on the resulting heat, Portman enrolled at Harvard to study psychology. As she told the New York Times, "I don't care if [college] ruins my career. I'd rather be smart than a movie star."
Of course, following The Phantom Menace with two further Star Wars prequels, there was little chance of her career derailing. Not all of her choices have been stellar --period biopic Goya's Ghosts flopped and Mr Magorium's Wonder Emporium was a severe misstep. Yet there's no stiffer critic of her work than Portman, who is as much of a perfectionist as Nina in Black Swan. "I'm very, very critical of everything. It's very hard for me to watch ... everything I would like to do over again. But I try not to, because it's completely impractical and a waste of time to think about that stuff. The problem is you can't do anything different."
If there's something quite controlling about Portman, she's not above just diving into her work. Black Swan was the second of four films she did back-to-back over the past 18 months. "It's been a very strange time in the film industry," she notes. "This film only had its financing for real just two weeks after we started shooting. Shooting was delayed four or five times. So I committed to things that I really liked -- none of which were really solid -- and then everything happened. Every film got financed. So I ended up doing four films in a row. It won't happen again!"
At least the other films were less taxing. She began with medieval comedy Your Highness, which she shot in Belfast, then comforted herself after Black Swan with Marvel blockbuster Thor and Ivan Reitman romantic comedy No Strings Attached (which she's an executive producer on). "They were both the gentlest of any work experience I could've gone into after this extreme situation," she says. Even so, she has no desire to step before the cameras again anytime soon. "It'll be a long time before I act again," she says.
By the time she does, there's a good chance her name will be prefixed with the phrase 'Academy Award-winner'.
Black Swan opens today
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