Tall and impossibly skinny, with impeccably arched eyebrows and cheekbones sharp as diamonds: on first impression, fashion’s latest darling looks no different to any of the other freaks of nature gliding through the offices of Storm model agency.

Except this season’s most-wanted model isn’t, for once, a she – it’s a he.

In an industry obsessed with the new, fashion has certainly found it with Andrej Pejic. Last month, the 19-year-old – already something of a name in menswear – caused a stir when he modelled womenswear for the Paris couture shows; he even wore a wedding dress for Jean Paul Gaultier.

Right now, Pejic is very much in demand. As well as editorials with prestigious photographers such as Steven Meisel and Mert & Marcus for Paris and Italian Vogue, he is the gender-bending face of the new advertising campaign for Marc by Marc Jacobs. Tonight he will be back in women’s clothing, modelling on the catwalk for Vivienne Westwood as part of London Fashion Week.

So which does he prefer – men’s or women’s? “I’m comfortable doing both,” he says, “although womenswear is more glamorous. The clothes are more exciting. In menswear I have to work more at having a masculine presence. But then that’s my job. If they put me in, say, a rubbish bag and I feel completely unattractive, I still have to show it to its potential.”

Pejic’s androgenous look is entirely his own creation – today, for instance, he’s wearing a light grey micro-mini dress, thick black tights and biker boots. “Around the age of 14, I decided to experiment with my look,” he explains. “As a kid, you get to the stage where you realise the gender barriers that exist in society and what you’re supposed to do and not supposed to do. I really tried being someone else during that period. It was hard for me – not being able to express myself and feeling I had to be someone else.

“But now I’m comfortable in my skin, and for my look to be celebrated is great. My look is very personal to me. When I started experimenting, it was a personal decision because I was unhappy. It wasn’t something I did for attention.”

Even on the closest of inspections, it is hard to discern Pejic’s gender: his complexion is a perfect peaches-and-cream, and there’s not a whisper of a five o’clock shadow. The only clue, perhaps, is his slightly protruding Adam’s apple.

Still, the female models he works with don’t seem too perturbed. “The girls don’t mind if I’m in their dressing room,” he muses. Neither are they annoyed that his flat-chested, snake-hipped figure is nigh-on impossible for most women to achieve. “Most of the girls are friendly. I guess they find me intriguing.”

What does remain intriguing, though, is why designers would want a man modelling women’s clothes.

“Andrej is the perfect coat-hanger,” says Clare Coulson, fashion features director of Harper’s Bazaar. “Clothes look best on someone who is tall and skinny, on a long and lean silhouette.”

Harriet Quick, Vogue fashion features director, agrees. “Andrej is incredibly beautiful with a very striking face – sharp angles and planes that look good on camera.”

Yet Quick believes his appeal goes deeper than that. “For the past decade, fashion has concentrated on the alpha male and alpha female stereotype. Now it’s all about questioning sexuality and blurring the boundaries. Andrej is reflecting our times – he’s what’s out there; he’s reflecting culture.

“It’s the same look we’re now seeing in music and with teenagers and twentysomethings on the street. He makes people open their eyes; makes them question how one presents one’s image. It’s attention-grabbing – it’s all about looking twice and asking questions. How? Why? And a good fashion image should hold your attention.”

Originally from Bosnia – his mother is Serbian, his father Croatian – Pejic was born shortly before the start of the Balkan conflict. His family moved to Serbia and, when he was eight, to Melbourne, Australia. “I had to learn a whole new culture as well as a whole new language,” he says. “At school, I was thrown in at the deep end. It took me a year to learn English.”

His refugee status has meant living as an outsider – and fashion is full of outsiders. “Fashion is quite inclusive and good at embracing different things and different forms of beauty,” he says. “It’s a very liberal industry. You can be yourself. Just not overweight,” he adds, drily.

Pejic was spotted shortly before his seventeenth birthday. “I was working in McDonald’s part time, and this guy came in – he wanted a cheeseburger. He then told me to see him at his modelling agency.”

Did he think you were a woman? “I don’t know, he didn’t say. Obviously, when I went into the agency, they figured it all out … But they signed me up right away.”

Initially, the agency was unsure about which direction Pejic should go. “In the beginning they wanted me to be more masculine – they told me to go to the gym because the menswear clients would like me more. That wouldn’t be such a good idea now because I wouldn’t be able to fit into womenswear.”

His friends and family have been supportive throughout. “Mum’s very proud. She finds every picture of me and has them on every wall. And my friends – well, since being a teenager, I’ve always been experimental. So they aren’t surprised. Obviously, they were surprised to see me in a wedding dress in a couture show. That was probably something they didn’t expect! But they’re all supportive.”

And how does the average Aussie macho male deal with his looks? “I’ve been getting chatted up by men ever since I was 14. In Australia, you’ve got your Greeks, and your Italians … I haven’t had any horrible experiences. Sometimes they’re shocked, but most of the time they still want to buy me a drink.”

Post-modelling, Pejic hopes to study either law or economics (before fleeing to Australia, his father was an economist and his mother a lawyer). “My favourite author is Leon Trotsky – the political philosophy and the way he writes is beautiful, and really relevant, too.

“But at this point nobody knows where this modelling is going. I usually have a plan in life – but this wasn’t planned. When I went to the agency, I was like, modelling’s better than a part-time job at McDonald’s. I thought I’d give it a shot. But it’s still going well so we’ll see. I would love to do Playboy with [the photographer] Terry Richardson. I love Playboy and Terry would be the person to do it.”

Along with the transgender model Lea T – the current face of Givenchy and Kate Moss’s co-star on the latest cover of Love magazine – Pejic is very much in demand. But fashion is a fickle business – something he is only too aware of.

“At this point, yes, everything’s going well. I’m still a sample size, so I can fit into designer womenswear. The only thing I have a problem with is my shoulders.”

Well, nobody’s perfect ..