Celine Dion, at the Met Gala, Is No One’s Paper Doll

“I’m never going to take it off,” Celine Dion said.

Mugging for a reporter’s iPhone camera with a voice you might associate with Dalmatian coats and Cruella De Vil, she repeated herself.

“I’m never going to take it off,” she said, head lowered, tone rising. “It’s mine! All mine!”

The subject wasn’t what she was wearing at the moment — a green metallic silk jumpsuit from Isabel Marant and Alexander Wang ankle boots — but an outfit by Oscar de la Renta, the one she will have on when the paparazzi go berserk on the Met Gala red carpet on Monday night. It is a creation that would seem as if designed specifically to test the internet’s breaking point.

[See all of the celebrities on the Met Gala red carpet here!]

To wit: a clinging champagne-colored bodysuit embellished with silvery sequins in fish-scale patterns, sleeves draped in 3,000 strands of floor-length fringe made from micro-cut glass bugle beads, all of it topped with a gold-tinted feather headpiece of singed peacock feathers by the milliner Noel Stewart because … of course.

It is an outfit that took 3,000 hours to create and that was inspired by one Judy Garland wore in the MGM classic “Ziegfeld Girl.” That costume was designed by Adrian to give the tiny performer a fighting chance when she appeared onscreen alongside Lana Turner and Hedy Lamarr.

Like so many of the specially commissioned rigs worn by celebrity Cinderellas at this annual tournament of fixed smiles, bulldozer fund-raising and cross-platform brand promotion, the Oscar de la Renta extravaganza is probably destined to return to its makers sometime after the clock strikes midnight.

One of the many ways that Anna Wintour, the Vogue editor and the Met Gala’s benevolent dictator, cannily rejiggered what was once an opportunity for society people to flaunt their couture finery is that a hefty percentage of its 550 attendees will be wearing clothes they do not own.

But wait. Perhaps Ms. Dion may not have to return an outfit that — with its references to Old Hollywood glamour, to both Busby Berkeley and Elizabeth Berkley and notionally to the theme of the new Costume Institute exhibition, “Camp: Notes on Fashion” — is like the raiment for a show business apotheosis. Perhaps she will retain the ensemble, which resembles what a sainted Vegas showgirl might wear to meet St. Peter at the Pearly Gates. Maybe she will purchase it.

“I buy,” said a woman whose personal fortune, amassed over four decades in show business, is widely estimated at close to a billion dollars. “I don’t beg for a gift.”

Anyone who knows Celine Dion can attest to that. Friends of the 51-year-old star point out that not only is she a clotheshorse, one whose increasingly adventurous wardrobe antics have inspired countless memes and what New York magazine’s The Cut referred to as a “Dionnaissance,” she is also a shopper.

“She can’t say no,” said Pepe Muñoz, a fashion illustrator and former dancer who is Ms. Dion’s principal stylist, sharing the duties with Sydney Lopez.

“Me, I love everything,” Ms. Dion concurred.

“You do,” Mr. Muñoz added. “You like everything.”

They were seated in a soundproof recording booth inside Studio at the Palms in Las Vegas, high in a tower of the newly renovated Palms resort. Ms. Dion was deeply tanned and had her hair skinned back in a taut ballerina bun. Mr. Muñoz, strapping in shorts and a T-shirt, looked as though he had come from the gym.

So easy were the two in each other’s company that it would be natural to think of them as a couple, a rumor that swept the internet after Mr. Muñoz, 34, accompanied Ms. Dion on a tour of the Paris couture shows in January and one the singer is quick to set right.

“The thing is that he’s my best friend, and we dance together, and he did so much for me,” Ms. Dion told the NBC staple “Extra” in April, adding that a hug from a handsome six-footer was something that, as a widow, she had not had for some time. But, she added firmly, “Pepe is gay.”

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By one of those fluky sequences that have become commonplace in the age of social media, the path to Ms. Dion for the Oscar de la Renta designers Fernando Garcia and Laura Kim led first to Mr. Muñoz.

“Instagram made Celine Dion happen for us,” Mr. Garcia said from the Oscar de la Renta atelier in Manhattan, where he was supervising 52 workers as they frenziedly assembled the Met Gala costume.

“Pepe and I have been Instagram friends since a couple years ago,” Mr. Garcia said. “So I wrote him a message saying, ‘You probably have a million requests, but by any chance would Celine like to come to the Met?’”

In short order it developed that she would. “I’ve designed for actresses before, and it was a little more tedious, but this was seamless,” Mr. Garcia said. “I was totally flabbergasted when, after a week, Pepe gave me a ‘maybe’ and then, within two weeks, a ‘yes.’”

Mr. Garcia soon sent the singer sketches that drew on his research into camp and discovery of a 1941 film about three show business hopefuls attempting to make it in the Ziegfeld Follies, spectacles that in the 1920s stood as the pinnacle of Broadway success.

“I’d never heard of the Ziegfeld girls before,” said Mr. Garcia, who is 32. “But the movie, the sets and the costumes are so glamorous and beautiful that we felt it would connect the aesthetic of camp to our house.”

Flying to Las Vegas for a first meeting with Ms. Dion, Mr. Garcia carried onboard a prototype that was his team’s interpretation of what he described as a “mega-fringed silver jumpsuit that Judy and a bunch of the girls wear” in “Ziegfeld Girl.”

“It’s very Vegas, and Celine to me is Vegas in the most beautiful way,” Mr. Garcia said, adding that when she first saw the dress, with its floor-length fringes, Ms. Dion immediately put on the soundtrack to “RuPaul’s Drag Race” and began to dance. “I’ve learned that Celine’s style choices have to speak to her. It’s not like she’s a puppet that’s told what to wear.”

It has always been that way, Ms. Dion said, ever since she was a child prodigy in Quebec, youngest of her parents’ 14 children, singing at a small bar attached to the family-owned restaurant.

“You’re born wanting to express yourself, and clothing is part of that,” she said. And it is through her unfettered style choices that she has lately revitalized her fan base. A generation too young to have known her megahits has discovered her anew as a kooky and ubiquitous YouTube presence prancing and posing and vamping across social media wearing couture finery in videos like the brief but addictive one she shot in Paris for Vogue in 2017 — a clip that even The Fader suggested expanding into a feature film.

Ms. Dion clearly enjoys toying with her new status; poking fun at her position as a freshly minted meme queen while professing not to know the meaning of the term; reveling in an ability to take irony to Susan Sontag levels when she stepped out in a “Titanic” sweatshirt from Vetements; out-camping camp by striking poses against the Bangkok skyline in an acid-yellow suit from Maison Rabih Kayrouz; attesting in Vogue to that cardinal rule of fashion: Never put comfort first.

“The day you start thinking about comfort, you’re getting old,” Ms. Dion said.

“Every piece of clothes brings me closer to creating a character,” the performer said that evening in Las Vegas as she sipped tea from a mug and anticipated the moment when she alights from her limousine at the Met Gala ready to do combat with seasoned red-carpet warriors like Lady Gaga and Kim Kardashian West.

She paused then to reflect on her life arc and the journey both from humble circumstances in Quebec to global stardom and from fashion afterthought to unexpected darling of that rarefied world.

“It was something that used to bother me a bit,” she said, referring to the decades it took style insiders to discover her hidden in plain sight. “It’s not like I’m going to call and say, ‘Can I be on the cover of Vogue?’”

Yet why not? “I feel like she’s having this extraordinary moment in fashion,” Mr. Stewart, the hatter, said by telephone from London. “She’s playful with it, and it’s rare to see someone enjoying this wonderful exploration of creativity.”

In fact, some of Ms. Dion’s oldest and most cherished recollections involve clothes. “I can remember a dress my mother made me when I was 6,” she said. “It was blue and had little white flowers, and I wore it with white gloves and a small purse of white lacquered bamboo.” Later Ms. Dion emailed a snapshot of herself in that very dress.

“I felt so beautiful in it,” she said. “I never wanted to take it off.”