Of all the many Madonna-related posts that have appeared on social media since it was revealed that the artist had been taken ill and forced to postpone her “Celebration” tour, one in particular stood out — not just because of what it said, but because of what it showed.

It was “M” herself, sitting conspiratorially at home with a pale bearded man — the designer Guram Gvasalia of Vetements, the subversively indie brand that upended fashion in 2014 by elevating the anti-glamorous. Mr. Gvasalia, it turned out, had been secretly working with her for the last five months on the looks for “Celebration.”

“Designing your costumes was such a privilege and honor,” he wrote next to the picture, adding, “now I understand why you are who you are. You are a fighter, you are an icon, you are THE QUEEN.”

If the timing seemed a little self-interested — new dates for the tour have not yet been announced — one thing was clear: Three decades after Madonna transformed the fortunes of another designer, Jean Paul Gaultier, via her “Blond Ambition” tour, the blockbuster that made Mr. Gaultier’s cone bras into a symbol of sexual rebellion and his name forever a part of pop culture history, Mr. Gvasalia is hoping that even the appearance of her imprimatur may do the same for him.

“I think it gives you certain recognition and credibility,” Mr. Gvasalia said of being chosen to work with Madonna. “When she can ask anyone in the world, and people will probably do it for free and be less complicated than I am, it gives you a certain security that you’ve done something right. It’s really a blessing.”

Certainly, if the tour happens, it will introduce Mr. Gvasalia, 37, to a much wider audience. He officially took over as creative director of Vetements only in late 2021, and before that was known primarily as the business partner and younger brother of Demna, the mononymic, much feted, latterly almost canceled designer of Balenciaga. (This despite the fact that the two brothers started Vetements together and Guram was as responsible as anyone for building it into a brand with 5.2 million Instagram followers and about 400 retailers worldwide.)

Along with the new Vetements collection, released digitally last week and featuring a bounty of grandiose proportions, the Madonna seal of approval may finally move him fully out of the shadow of his brother.

Though even there, his ambition, like his clothes, is outsize and impossible to miss. He did say he had made his trousers, puffers and skirts 16 times larger than normal in part because he was “trying to understand what is the maximum oversize I can make that still looks like clothes and you can wear but nobody else can make anything bigger.”

Consider the Kardashians

History, not to mention literature, is rife with stories of sibling love and rivalry. It is one of our strongest, and most fraught, bonds. While fashion has had the occasional sibling partners — Mary-Kate and Ashley Olsen of the Row; Kate and Laura Mulleavy, who founded Rodarte; Dean and Dan Caten of Dsquared2 — never before have two siblings who started together ended up quarterbacking fashion teams that are, if not exactly playing the same game, certainly aiming for a similar league.

“You guys really misunderstand how it is,” Mr. Gvasalia said, referring to the fashion media. He was sitting on the terrace of the Aman hotel in New York, drinking a Coke and wearing big black boots with barnstormer platform treads, a white gold Cartier nail bracelet, two Cartier gold chain necklaces, a diamond wedding band, a Cartier panther ring and gold grills on his teeth.

“My brother is six years older. When I’m in the second grade, he’s in the eighth. He got certain opportunities in life earlier. But if you consider where I am today, where my brother was when he was my age, I think I’m far more advanced.”

Mr. Gvasalia tucked his hands through the giant rips in the thighs of his oversize black jeans as if they were pockets and took a breath. He can be charming and erudite and breathtakingly ego-centric, all at the same time.

“I give you the best example that everyone can relate to,” he went on: “The Kardashians. You have Kim, who is a great person — we think she’s phenomenal — and you have Kylie. Kylie’s the young generation. She’s been very successful without having sex tapes, without having to go through all the things that her sister had to go through. Another example is Venus and Serena Williams. They’re both fantastic. But somehow there was a point where Serena managed to kind of take over.

“I think my brother is very talented, but I have a completely different approach to things. He had his good run of 10 years, and I think his era is slowly going to its finish line. Now it is my time.”

Is that why he chose to post his Madonna reveal not long after the Balenciaga couture show?

“It’s just the right time for us, after the momentum from our show,” he said. Then he added, “Balenciaga always releases news on the day of our show, so I feel it’s only fair.” “Always” may be something of an exaggeration, though he did point out, “They announced Demna’s appointment on my birthday.” That was true (Oct. 7, 2015) though it’s a long time to carry a grudge.

Sometimes it’s hard not to wonder if Mr. Gvasalia knows what he is saying — or how it may be received — or if he is purposely trying to roil the pot. After all, said Julie Gilhart, chief development officer and president of Tomorrow Consulting, who started following Vetements not long after its debut: “There’s nothing sloppy about Guram. I sat with him once in an airport lounge and saw the way his bag was organized — it was perfect. Everything had a place. He never stops thinking. And he is very precise.”

‘It’s not enough to be good. I need to be very good.’

Currently the two Gvasalias are trying to keep their public selves separate. Demna dropped his surname in late 2021. Guram said he would rather I not speak to his brother for this piece. When I requested comment from Demna anyway, Demna replied, via a spokeswoman: “As I’m at Balenciaga, I prefer to generally focus on that when speaking to press or in a professional context. My experience at Vetements was amazing, but I’m leaving it in the past as fond memories.”

Still, it’s almost impossible to disentangle their stories.

Demna and Guram were born in Sokhumi, Georgia. When Guram was 7, civil war broke out and the family fled home, leaving everything behind. They spent a month lost in the mountains before eventually making their way to Düsseldorf, Germany, where the boys grew up. (In 2021, Guram told Forbes Georgia that if his family had stayed in Georgia, “I would probably be running for president.”)

“They have a shared sense of survival that makes them very disciplined and resilient,” said Jean Delmas, who, along with his partner, Heidi Yang, has been working with Guram as a sales agent for almost a decade.

Parental pressure dictated that Guram, like his brother, go to business school, but he also earned a master’s degree at the London College of Fashion (he wrote his thesis on Martin Margiela), with after-school stints at Burberry and Selfridges. In 2012, he self-published a book called “Size Zero: A Guide to Spiritual Management” about “how you need to get rid of everything in your head and just listen to your heart.” Two years later, he joined forces with his brother, who had been working at Margiela and Louis Vuitton, to start Vetements.

They decided to frame their new label as a “collective” because, Guram said, “we didn’t want to put ourselves out there. It was always just about making the clothes and making what we felt was right.” If pressed, they would say Demna was the creative one, and Guram the businessman.

“Everyone was kind of doing everything,” Guram said. “You’re a designer, a manager, a cleaning person; everything.”

“No one really knew what was going on,” Ms. Gilhart said. “But anyone who knew anything about the business knew Guram was a big part of it. He hears and sees everything.”

Vetements detonated in the fashion world so effectively that in 2015, Demna was hired at Balenciaga. The next year, Guram

relocated to Zurich, along with the business — a decision he said was less related to taxes than to the desire to get away from the fashion establishment. Zurich is German-speaking; German is one of the four languages he speaks fluently (the others are Georgian, Russian and English, though he is also pretty capable in French and Italian).

Demna and his husband soon followed, but by 2019, Demna announced he was leaving Vetements to focus his attention on Balenciaga; he has since left Zurich for Geneva.

“I find the world has for me completely different expectations than from everyone else,” Guram said of the pressure he now feels. “The moment I do something, the bar is really super high. Because we changed the industry, because we were so shocking. And because my brother has a big name and has done a lot of things. Having him in my life puts more challenge on me. You know, it’s not enough to be good. I need to be very good.”

Lagerfeld dreams

According to Mr. Delmas, the move to designer was less of a leap for Mr. Gvasalia than the popular narrative may make it seem. “Even when Demna was there, Guram would edit the line,” Mr. Delmas said. He would “add some pieces to what was in the showroom. He has a good idea of what is viable commercially.”

Still, Mr. Gvasalia has begun to differentiate his Vetements, focusing more on tailoring and luxury fabrics. It is certainly priced like a luxury brand, with leather coats between $3,000-$10,000, and dresses that can run from a few thousand to more than $75,000. “The styling seems more involved, the fashion seems a little more high-concept,” said Noah Johnson, the global style director of GQ, who said he was beginning to wonder if “maybe he was the mastermind of Vetements all along.”

The most recent collection, Mr. Gvasalia’s third, was rife with Easter eggs that reflect his dreams, goals and hangups. Alongside the acres of puddling denim paired with narrow corsetry and swaddling down were two very long, very Chanel-like coat dresses, shown over jeans, a nod to Karl Lagerfeld, whose longevity in fashion made him a role model for Mr. Gvasalia.

Also included: a choker necklace with an “M” at the front, a relic of his work with Madonna (she wore a similar necklace in an Instagram post in May). And a group of bell-shaped gowns with skirts six meters in diameter, integral gloves and face masks that, as Nicole Phelps wrote for Vogue Runway, bore a marked resemblance to the bell-shaped dresses Demna made for a Balenciaga show in 2019, spliced with the full-coverage bodysuit Balenciaga gown Kim Kardashian wore to the Met Gala in 2021.

“Those dresses, they’re much, much smaller,” Mr. Gvasalia said of the Balenciaga looks. “They have a completely different construction. And honestly, I think all the brands in the world have done these kinds of dresses. I also think if you look at them next to each other, ours are much better.”

‘There is still something coming.’

Mr. Gvasalia has spent the last five months hopping back and forth from his headquarters in Zurich to showrooms in Paris to New York, where Madonna is based.

In Zurich, he lives in a house on a lake just outside the city with his partner of almost 10 years, a Russian-raised entertainment mogul who asked to remain anonymous but has pitched in with the Vetements business so Mr. Gvasalia can concentrate more on the creative side. They also have an apartment on the Avenue George V in Paris, just across the street from the Four Seasons hotel (where his parents stay when they are in town) and up the street from the Balenciaga couture salons. They are, Mr. Gvasalia said, “perfect” together.

When Mr. Gvasalia comes to see Madonna in New York, he stays at the Aman. He does not collect art, but he does collect very high-end watches (Patek Philippe, Audemars Piguet) as well as Hermès bags (“all in croc”); vintage Margiela, Gaultier and Montana; and nice cars. (His current ride of choice is a Rolls-Royce SUV.)

For years Mr. Gvasalia was very shy and refused to have his picture taken, Mr. Delmas said, but recently he has done something of an about-face, creating a public persona — much as Karl Lagerfeld did — that involves sweeping leathers with jutting shoulders and cinched waists, giant ripped black jeans, giant T-shirts, black shades and lots of jewelry.

He also acquired some custom-made grills from a dentist turned jeweler in New York whom he called the No. 1 grill person in the world. “He’s from Israel but moved to New York and couldn’t get his license,” Mr. Gvasalia said. “He started to see rappers wearing the golden teeth, but the quality was horrible, so he said ‘Oh, I’ll make it properly for you.’ He does grills for Pharrell, Madonna.”

Mr. Gvasalia designed his to match his watches: a white and rose gold set to go with his white and rose gold Patek Nautilus. He likes the grills because they are not permanent, but, he said, “they add to the look, especially in summer, when you just have a T-shirt on.”

During the January men’s collections, show goers began noticing Mr. Gvasalia everywhere: in front rows and at clubs, in Daily Mail celebrity gossip columns holding hands with Avril Lavigne. He is friends with J Balvin, whom he met about a year ago when Mr. Balvin DM’d him on Instagram. Now, Mr. Balvin said, they text almost every day and “spend hours talking about fashion, watches, music and traveling — gossiping.”

Still, he often works until 5 or 6 in the morning, returning again at 10 a.m. His most recent show was the second most viewed spring 2024 men’s collection on Voguerunway.com, coming in just after Vuitton and just before Prada. Mr. Gvasalia is, Vogue wrote, “on a roll.” (Not long after, Beyoncé posted a photo of herself on Instagram in a pair of Vetements jeans.) According to Freddy Barassi, the vice president for men’s wear at Ssense, it has stocked Vetements since 2015 and seen double-digit growth each season.

Next year will be Vetements’ 10th anniversary. Mr. Gvasalia has plans. They are, characteristically, not small.

“Looking at people my age now, I’m not sure who is the competition,” he said. “I had dinner yesterday with Sam Worthington. You know, the actor from ‘Avatar.’ I said, ‘Sam, do you think you’ve had your biggest movie yet?’ and he said, ‘No, I think it’s still coming.’ And I feel for me, there is still something coming very big. I would not take a job today somewhere else. But one day if Chanel comes? I would not say no.”