The selfie made man

Then there’s Kendall Jenner, of course. The 19-year-old social-media supe, and Rousteing’s good friend (natch), points out that she is “the star of the whole thing, or whatever”. Having already been snapped by Mario Sorrenti, today she is being filmed leading a Balmain x H&M clad crew of fashion tuffs having a bling-off with some less sparkly hoodlums on a futuristic subway set, the size of which would not shame Star Wars. Somewhere above, Rousteing, couture’s current It boy, is in a control booth faux DJing, while lasers shoot about everywhere.

Surely this operation must be costing H&M well into eight figures — though I imagine the numbers have been carefully crunched. From Stella McCartney, the year after Lagerfeld, to Alexander Wang last November (via Cavalli, Comme, Versace and all the others), its designer collaborations have become such ruthlessly effective brand-builders, it hardly needs the clothes. Though there have been some doozies along the way. Anyone who managed to nab a faux-fur Lanvin jacket for £80 is probably still psyched with it (or made a tidy profit on eBay: the H&M collabs can go for a song when resold online). Ditto a pair of Isabel Marant boots.

Gigi Hadid, Olivier Rousteing and Kendall Jenner in Balmain x H&M

Of course, the 9am bunfight on launch days, typically in November, is a fash-pack tradition now, equivalent to the first day of grouse shooting for terminal trendies. Donald Schneider, H&M’s creative director, says the top fashion editors even “send bike messengers with a shopping list”. A bit unsporting, perhaps, when it’s supposed to be a way for kids and fashion fans to look ballin’ when they’re boracic.

Actually, you can’t be too skint any more. Some of it is good value — T-shirts for £25 and loads of great party-season trousers for about £60. But one of Rousteing’s dresses — slashed well above the knee, of course, and with that fabulous, heavy, sequin embroidery you sometimes see covering Kim Kardashian’s second-favourite erogenous zone — costs £399.99. Several others are well over the £200 mark, and there are heels for £200, handbags at £150 and bracelets for £120. “Not everybody will be thrilled about it, it’s not the normal fashion you expect at H&M,” says Schneider. “But I think that’s what makes it special — to offer something to the client that they would not be able to get anywhere else for the money.” Hmm. A party frock from mainline Balmain can cost £20,000, so he’s not technically wrong. But doesn’t handing over £400 for an item at the place you pop into for emergency knickers feel a bit steep?

What was Rousteing thinking? “My designs are really couture, really French and really luxury,” he says, sheathed in a black suit with his heavy French accent at full flute. His spookily perfect bone structure can look a bit fibreglass online, but he has kind eyes and a surprisingly calm disposition in person. All bets are off, apparently. “Because of my age, you can mix couture with pop culture, which is what I’m doing with Balmain and my buyers. And they love it.”

This has been his party trick, of course. Reinventing a fusty, snow-white Parisian fashion house as the label of choice for Rihanna and the Kardashians, and, by extension, all their fans who don’t see the point of subtle glamour on a Friday night. They might not be able to afford much of it, but it has cannily allied the brand with “youth” in the heads of shoppers. Naturally, Rousteing plays this up to the max. “There is a really big statement that is going to happen in fashion,” he says. “Who is going to look cool and young, and who is going to look old and irrelevant.” Ouch. Look out, Lanvin.

Starting life in a Gironde orphanage in 1985, Rousteing was adopted as a baby. He was pathologically driven as a child, he says, partly because he felt so abandoned. “I was really good at school, trying to please my parents so much because I didn’t want to go back to the orphanage,” he smiles. He left for Paris at 17, originally to study law. “For 10 minutes, just because I liked the boys in the school... Just kidding.” But fashion was his calling, and, after a brief stint training, he went to work for Roberto Cavalli in 2003.

Clockwise from left: white blazer, £80, green drop earrings, £25, embellished dress, £400, and stripy trousers, £60, Balmain x H&M. Main picture Kendall Jenner and fellow models on set for Balmain x H&M.

He moved to Balmain five years later as an assistant to Christophe Decarnin, and was offered the top job in 2011, when Decarnin left. What seemed to irk French fashion’s old guard even more than his age (he was only 25 at the time) was the colour of Rousteing’s skin. Whatever you think of his hemlines, he’s been brilliant at breaking down depressingly stubborn race barriers in high fashion. “So many different cultures,” he says happily of all the models hired for today’s shoot. “I was speaking with the dancer, who is half Mexican, half New York. There’s Kendall, there’s me, there’s Hao Yun Xiang, who’s Chinese, all together. I love that. It’s so different, so interesting.” Though I don’t think he’s just a wishy-washy, heal-the-world type. Did you ever think you would do this well this fast? “Of course,” he says, with superb Gallic disdain. “I’m really pushy. I have no patience at all. It’s not tough,” he shrugs.

H&M hired him because he knows how to play the game and has the perfect connections. Nearby, his bessie pal Kendall Jenner is done up like the world’s skinniest Christmas tree decoration in a sternum-baring green sequined cocktail dress (£120). In between setups, she flops on a sofa and tells me about how she came to post the most liked image ever on Instagram. “Oh my God!” cries Jenner of the shot she posted of herself with her hair arranged in hearts that 3m people have“liked”. “Maybe you don’t do this and I’m just a weirdo, but I was having such a bad day that I fell to the floor and screamed. I was on a yacht, so I don’t know why I was having a bad day. It was, like, the greatest situation. I was, like, ‘I’ll post it — it’s cute.’ Never would have thought that would have happened.”

If this sounds vaguely impenetrable, rest assured the possibility that a random moment of teenage tomfoolery will go viral is the holy grail of fashion marketing these days. I wonder if, 11 years ago, when Kaiser Karl took the then risky decision to hop into bed with the high street, he knew this would be the future of fashion? Rousteing sees no difference between haute couture and high street when you’re out to make an impression. He slips into full H&M PR mode for his glitter-candy evening wear and sexy, sports-luxe day stuff for the boys (menswear makes up 40% of Balmain’s sales, according to Rousteing): “What is important with Balmain is it’s going to give you the attitude.”

Increasingly “attitude” is an online affair. It figures that his gaudy H&M designs, a very particular in-your-face aesthetic, really ping — might look best, in fact — when seen in a social-media post on an iPhone. Enter the campaign’s star, Jenner, and her 38m Instagram followers. “Kendall is one of the hottest girls in the world,” he says. “She’s such an icon — not just as a model, but as a girl. A lot of girls are following her because they want to understand her life. To eat like her, to dress like her. Being popular — there is nothing wrong about it.” Fair point.

If so, however, what does luxury mean now? “Today, luxury means success,” he says simply. Not least his own. “Before, I was the baby of Balmain, and today Balmain is my baby. If you don’t like me, you don’t like Balmain,” he says. “I’m just waking every morning to make beautiful things and see beautiful people. I’m not saving lives. I’m not working in surgery or at a hospital. Just enjoy and have fun.”

With that, a swarm of publicists, make-up artists and noir-clad runners practically levitate them back to set. The lights turn, the music thumps and the director calls action, Masterpiece marketing, I think. Regardless of whether you manage to get your hands on a bit of Balmain x H&M this year, the images will be everywhere, giving the likes of Rousteing and Jenner a serious fashion moment, while making you feel a teensy bit chicer the next time you pop into H&M for some basics. Like I said, it’s all terribly modern, if rather pricy.

Balmain x H&M launches online and in store on November 5