My interview with Russian ballet star Natalia Osipova has not got off to the best of starts. 

So guarded is the darling of the Royal Ballet – who has now segued into modern dance with a risqué new show at Sadler’s Wells – about her love affair with Sergei Polunin, the brooding enfant terrible of dance, that I worry their relationship may be on the rocks.

Dubbed ‘the Brangelina of Ballet’, the two have been together for over a year now. They fell in love while dancing Giselle together in Milan, which sounds so sexy and romantic it makes me feel faint.

Their chemistry – on and off stage – seems quite explosive. I imagine they have fiery rows – and even more heated, er, reconciliations. But to my horror, Natalia says at first that she doesn’t ‘want to discuss our feelings for each other in public’. What?

The dancer, who turned 30 in May, is at pains to demonstrate how much she has grown since her relationship with Sergei began last summer – when, clearly in the throes of early passion, she made the gushing admission that they found it hard to be apart for more than two days.

Sergei – who left the Royal Ballet amid drama and allegations of drug-taking just before Natalia joined as a principal, giving their union a star-crossed twist – has said that he never wants to dance with anyone but Natalia again.

But the Natalia I encounter today – busily rehearsing a contemporary dance ensemble specially choreographed for her by Sidi Larbi Cherkaoui, Russell Maliphant and Arthur Pita (Sergei dances the latter two works with her), which will return to Sadler’s Wells later this month after a successful summer run and then transfer to New York – is altogether more composed than she has seemed before.

Despite having made London her home since 2013, Moscow-born Natalia still struggles with the language. ‘This is my biggest challenge. I need to study English and to learn it properly, but there is never the time,’ she sighs.

With the help of a translator, she explains how she has evolved of late. ‘I am a highly emotional person, confident and bold, but ruled by my emotions. I am capable of a sort of madness. If I am feeling emotionally charged, I could buy a ticket and move to another continent!’ she exclaims.

‘I am too spontaneous sometimes. But now that I am 30 I think I am becoming more balanced and getting better at thinking before I speak or act.’

Perhaps we can rewind a few months for the sake of this interview, I joke. I am not sure my humour translates. She has previously admitted that, due to their similar temperaments, she and Sergei have been known to clash.

‘We are two strong characters and at times this creates friction, but you learn to make compromises and to find ways of not arguing with your partner,’ she explains. ‘Sergei is a very fiery and emotional person, but he is emotional in a different way to me. I can’t quite explain it. We are different people, of course…’ She trails off, and I get the sense she is wading through verbal quicksand here, resisting the Brangelina-isation of them as a couple, while glorying in the loved-up state she has found herself in.

She doesn’t care what others might make of their relationship, she says. ‘I am sure there were people who had something to say on the matter, but I am not concerned about it.’

And though she is a self-confessed hot-headed leading lady, Natalia reveals that, when dancing with Sergei, she enjoys letting him take control. ‘As a very strong person, I have always tended to take the lead, but with Sergei, it is he who leads.

‘That is the dynamic that works best for the two of us. As a female it’s an interesting feeling and state of mind when the male can take charge on stage. It has been something new for me and I like it.’

I mention Sergei’s comment about not wanting to dance with anyone but her. ‘We have both grown up since then. It was probably said in a moment of emotion! 

‘We are at a different point in our relationship now. We are very solid and open with each other. We understand that work is work and we both have to make professional decisions. We wouldn’t restrict ourselves to only dancing with each other, because it wouldn’t be the best decision for our careers.’

But wouldn’t she feel jealous watching Sergei dance with another? ‘On a personal level, it would be bad to see him with someone else, but professionally, no,’ she insists. ‘I am very lucky that I am not and never have been a jealous person.’

This trait must have come in handy when Natalia’s relationship with her former boyfriend, Russian ballet star Ivan Vasiliev, broke up shortly before she moved to London and took up with Sergei.

The pair had been the golden couple of the Bolshoi, but rumour had it (supported by Vasiliev’s own admission) that he left her for a younger dancer – ballerina Maria Vinogradova, to whom he is now married. (This scandal was referred to as ‘the Bolshoi love triangle’.)

‘I don’t listen to any gossip,’ Natalia says curtly. ‘Ivan and I have a good relationship. We are in close touch. We don’t see each other often, as we live in different places, but when we do it is very warm and fine. We have danced together since we split and I would happily do so again.’

For the moment, though, Natalia remains focused on dancing with Sergei in the independent Sadler’s Wells production, which represents a departure for her as a classically trained ballerina.

Staged in three parts, it involves a lot of strutting and shimmying, with costumes that could not be more unlike the restrictive, conservative ones worn in ballet.

The pair entwine themselves seductively in distressed jeans and T-shirts, perfect for showing off Sergei’s extensive collection of tattoos. ‘The less I wear, the more comfortable I am, so I loved this costume,’ says Natalia.

‘It felt so much lighter and freer than ballet clothes. The best part has been working directly with brilliant choreographers and creating amazing poses together. My body has had to get used to using different muscles, but I am loving it.’

And how does she feel about her paramour’s tattoos? ‘Actually, I like them,’ she giggles. ‘I think they reflect his personality quite organically. I am not planning to get any myself,’ she adds hastily. ‘I don’t think they would be suitable on my body.’

Lovers on stage and off, dancing their hearts out in denim, and a male lead who could be described as ‘a bit of rough’… comparisons to my favourite film, Dirty Dancing, are impossible to ignore.

Does Natalia feel a bit like Jennifer Grey to Sergei’s Patrick Swayze? ‘I love that film. It’s very iconic, but for some reason I never made this association.’

Like Dirty Dancing, Natalia Osipova and Guests, as the performance is titled (I wonder how Sergei feels about that), is about love.

‘It is set in the 1960s and about two people who are in love; the male character dies and she continues loving him [in one scene she tries to pull him from the grave]. It is deeply romantic, about love that surpasses death – not just love, but loyalty; about a woman who thinks she’ll never be able to be with anyone else.’

Given that Natalia commissioned the three pieces – each one written for her by a top choreographer (such is her star quality, they presumably jumped at the chance) – I can’t help but think that this gives an insight into the depth of her feelings for Sergei.

Having initially said that she didn’t want to discuss him, Natalia has let the word ‘we’ creep into her speech when discussing the man with whom she has shared a stage and now a life and a home.

‘We love Japanese food,’ she says in response to my question about what she likes to eat. ‘We just like to go to small local restaurants, nowhere fancy.’

 On a perfect weekend, ‘we like to walk around the canals in our neighbourhood of Little Venice and maybe visit London Zoo. We spend as much time outdoors as we can. We like to lie in bed as long as possible first, though, to feel fresh. Ideally, I would lie in until about 11am.

‘We like to cook together, although I am not a very good cook. Sergei is much better than me. He cooks mostly.’

It all sounds very domestic. Do they want children? ‘I think that should be the aim for every woman. That’s my point of view,’ says Natalia, somewhat cryptically. ‘We know each other’s families very well now too; there are good relations between the families.’

It was, in fact, through family that the two came together. Natalia is exceptionally close to her parents, who still live in Moscow, and tries to visit as often as her schedule allows.

‘I feel a huge responsibility to make them proud and pay them back for the sacrifices they made to allow my ballet career to happen. They were not well off – my father is an engineer and my mother doesn’t work – but they always found a way to give me opportunities, whether it be taking me to the theatre or finding money for dance lessons.’

Initially, Natalia was not drawn to ballet. She started out as a gymnast and it was her parents – presciently spotting her greater potential for dance – who insisted that she make the transition. ‘I wasn’t happy about it at first,’ she recalls, ‘but gradually I got used to it, and now I am so happy that I made that change and so grateful that they insisted.’

When Natalia was due to appear in Giselle in Milan in 2015 and her partner fell ill, it was her mother’s idea that she contact Sergei to see if he might stand in, so she sent him an email.

‘He had at the time gone off by himself.’ (In a strop, so it was said, after spiralling into unhappiness and cocaine use, to explore a freelance career as a dancer/actor/model.) ‘My mother had seen him dance and suggested he might be a good pairing for me in this role.

‘That’s how it all started. I knew of his excellent reputation as a dancer. And as to his other reputations…it was his dancing that I chose to focus on and that made me write to him,’ she says diplomatically.

And was it love at first sight? ‘Yes. From the first meeting there were very strong feelings. We both understood there was something special.’

This attraction was palpable – and their performance so widely acclaimed that they will reprise the roles in a production of Giselle in Munich this month.

‘It was very emotional dancing with Sergei that first time,’ Natalia reminisces. ‘We came together as individuals, with our own experiences, and something a bit magic happened. I think the audience could feel it. It was emotionally very charged. I think they had a great time watching us in that show. Giselle is so romantic and will always be my favourite ballet.’

Natalia leads a highly regimented life as a dancer, with long days of rehearsals and few breaks. She has, like most top ballerinas, been dogged by injury. ‘This is part of my professional life and something I have to live with, but my injuries aren’t giving me too much grief at the moment.’

Though only 5ft 5in tall, with tiny bones, she feels that her body is oaf-like by dancing standards. ‘It has been a challenge,’ she sighs. ‘I have to be very strict with what I eat. I have nothing made of flour and no sugar. I eat mostly salads.’

Having a man in her life who understands the sacrifices required of her must make things easier? ‘I don’t know any different because my boyfriends have only been from the dance world, and it seems to have worked out pretty well so far,’ she says coyly. ‘It’s a nice feeling to be with someone who understands.’

Natalia once said she found pre-performance nerves so bad that she wanted to run away. Having Sergei by her side makes a difference.

‘With age, I have got better at managing the nerves. Now I know how to not let it get to that point. I arrive at the theatre much earlier and spend some time on the stage, living the life of my character before the show. That is really helpful.

‘ It’s such an individual state, so even Sergei can’t always help me, but it is great when he’s there beside me. He can try to calm me down. Even just the way he says “good luck” can make me feel much better.’

When I ask if Sergei would consider a return to the Royal Ballet, as some have speculated he might (it would, after all, make sense with her there), Natalia will only say, ‘I can’t answer that. It is a question for him. But he is an outstanding dancer and I think it would be really interesting if he did decide to.’

Either way, the pair intend to partner on stage as much as possible – even if not exclusively. ‘We want to find a way to do more together,’ Natalia reveals, sounding for a moment a bit too smitten, and then correcting herself.

‘I mean, I would like to think that of course we are professionals, so we would dance our best with anyone. It shouldn’t make a difference, but…it is such a special feeling to dance with the person you love.’