There's something very insular about ballet dancers. You tend not to see them much at parties. What with classes and rehearsals all day, performances in the evening and dieting in between, they don't get out much. Indeed, the one scene in Black Swan that didn't ring true to me was when Natalie Portman and Mila Kunis went clubbing. I think not.
So I shouldn't have been surprised when I met the Royal Ballet's prima ballerina Sarah Lamb that she had come straight from a rehearsal and was carrying her tutu and dancing shoes.
Though when she stretches her leg across the sofa and fixes me with the disarmingly wide blue eyes that dominate her elfin face, one has to admit that ballet's gain is clubbing's loss.
Lamb, a 30-year-old Bostonian, is one of the company's brightest stars. In recent weeks she has been one of two ballerinas to create the title role in the new ballet Alice's Adventures in Wonderland, she has taken the title role in Cinderella and on Saturday she dances the title role in Manon. But first she has to sew some shoes.
I confess to a double-take at this. The Royal Ballet's international stars have to sew their own shoes? Isn't that akin to Wayne Rooney having to clean his boots? Shouldn't sewing the ballet shoes be a job for teenage wannabe dancers?
"I sew four or five a week," says Lamb. "And I use a razor blade to pare them down. Today in the Manon rehearsal the floor is dirty in the first act, then you get blood on a shoe in the next act, so new shoes are needed. I believe there used to be a boy here once who did it for £5 a time, but he has gone."
It sounds like a job for the Royal Ballet's Equity rep, who just happens to be Sarah Lamb. Before discussing the day job, I am quite curious about the world of negotiation at the Royal Ballet, perhaps from what I know of ballet dancers, some of the last smoke-filled-room negotiations left in the trades union movement. "I did it in Boston and there were more tensions there between dancers and management. Here it's very different. The management have all been dancers, so they are very sympathetic. The management are aware that dancers are worked very hard, but the schedule is manageable.
"Sometimes the corps de ballet gets very tired, though. They have performances in the evenings, then rehearsals all day. They are 'on' all the time."
Well, if Sarah Lamb negotiator, can touch the hearts of the management in the way that Sarah Lamb dancer, can touch the hearts of the audience, pay rates should be improving soon. Indeed, Ballet.co.uk website said: "Her cool elegance and unerring precision could make you weep."
I found in her creation of Alice a rare mixture of comedy and vulnerability; a vulnerability that can be heart-rending. The mixture was also apparent in Cinderella. Manon is a different kettle of fish. To quote from the posters currently on the London underground, it is "a sultry tale of dark desire".
Is that you, Sarah?
She neatly sidesteps that one, responding: "What appeals to me most about Manon is that she makes a mistake that she realises and then tries to rectify. We all do that once in our lives."
And what was Sarah Lamb's big mistake? "It was probably when I was a teenager, being a really horrible teenage girl to my parents; very self-centred.
"I did whatever I wanted and didn't communicate with them. And wasn't a loving person back."
Her parents, both teachers, weren't actively keen for her to be a dancer and suggested firmly that she apply for university, even though she told them at the age of 14 that she might not go. Then, at 17, she was offered a dancing job and they have been supporters and often in the audience at her shows since.
Sarah Lamb's roles and her childhood seem to connect more than once. "I have felt quite connected to Alice in Wonderland," she says. "My grandmother emigrated to the USA from England after the Second World War. She was a speech therapist and worked with children with cerebral palsy. In 1953 she created the first summer camp for children with these difficulties. It was called Jabberwocky. My father painted a school bus for them with pictures from Alice. The camp was in Martha's Vineyard. I spent every summer there."
Even before arriving at the Royal Ballet in 2004, she was awarded a Presidential Gold medal and invited to perform before the then President Clinton in Washington. What did he say to her, I wondered. "He just said: 'Congratulations'," she replies, but she endows that one word with a deep, southern drawl. "He had quite a ruddy complexion, I remember. We were in the rose garden. He was very warm; definitely had charisma.
"I also remember that I kept setting off a metal detector because I had a lot of hairpins in my hair."
She has said that it took her time to make friends at the Royal Ballet, but now does have good friendships. Without wishing to bring in any rivalry parallels from Black Swan – something she rejects firmly – I do wonder how close the friendships are in the hard-working, intensely-focused world of ballet.
When, I ask, did she actually go out for a drink with a fellow dancer from the company?
"I spend time with them here. But off work I keep separate. I spend time with my husband." He, too, was a dancer but is retraining as a landscape designer.
One thing they don't do together is watch television. The Royal Ballet's feisty star refuses on principle to buy a licence.
"I don't have a TV. They charge you a licence in the UK, so in true Bostonian fashion I refuse to pay the tax. It's an American thing. I love the BBC, really, though some of the things they show I don't like. That astronomer, you know, the physicist [Brian Cox]. I hate the way he speaks." It's a rare piece of negativity from a woman who exudes a natural charm, who indeed once said of performing the title role in The Sleeping Beauty: "I feel very much at home with Aurora's shyness and wonderment and also try to show all the gifts she has received from the fairies: purity, charm, musicality."
She takes a more qualified view now of the affinity with Aurora. "I think I'm very much a realist, so I'm a bit critical of myself. I'm never satisfied with my performances.
"But at the same time I look outside and look at the trees and think how beautiful they are. I think I do try and appreciate that what I get to do is a very real privilege."
And as she never watches TV, what does she do when she is not dancing?
"I like the theatre," she replies, "and I read a lot, though not as much as I should. And I sew a lot of shoes."
'Manon', Royal Opera House, London WC2 (020 7304 4000) to 4 June