How The Kardashian´s Get All Their 90´s Vintage

In a recent episode of Keeping Up With the Kardashians, Kourtney Kardashian FaceTimes Kim to get her opinion on an ultra-short mini dress covered in a mosaic of cotton candy-colored rhinestones.

"It's vintage Dior," the doyenne of reality television brags of the piece, which she winds up wearing to Kylie's skincare launch event. The Kardashians aren't shy when it comes to obsessing over throwback fashion, but tracking down high-end garments of yesteryear is easier said than done thanks to a surge in popularity and a finite supply. Kourtney's sparkling Dior number was actually borrowed from an ultra-private showroom hidden away in a Hollywood Hills home that celebrity stylists consider to be the mecca of high-end vintage marketplaces. All 3,500 pieces available for rent are carefully curated by Chicagoan Janet Mandell, a longtime couture collector and one of the industry's best-kept secrets.

Mandell flies under the radar, but she's responsible for the sartorial success of dozens of celebrities, including Priyanka Chopra Jonas, who donned her ruched cherry-colored Tom Ford belted dress for an interview on The View. Mandell also sent Gigi Hadid a 1980´s Chanel number to wear at Karl Lagerfeld's memorial "Karl Forever," this summer.

The collector's eponymous showrooms (she's also got a second location in Chicago) contain over $2.3 million of drool-worthy designer rags, from archived Chanel suits to Saint Laurent dresses with diving décolletage to glittering Van Cleef & Arpels necklaces. Her collection of 1990´s Manolo Blahnik sandals would send Carrie Bradshaw into cardiac arrest.

Although Mandell does offer fresh-off-the-runway finds, it's her covetous trove of 1990´s Valentino, Gucci, Versace, and Chanel—which makes up about 20 percent of her inventory—that attracts her celebrity clientele. It's also what sets her business apart from other resale or renting competitors like Rent The Runway, The Real Real, and Armarium.

"All these really ageless fashion girls like Bella and Gigi [Hadid] and Kim and Kourtney [Kardashian], they don't want anything that's current. I have the sickest Chanel suits that I bought off the runway last year and they love it, but they're like, 'You know what Janet? I can't wear that," Mandell tells ELLE.com. "They don't want to be seen in something that somebody else might possibly wear. They want Pucci 1990´s, Versace 1990´s and it has to be Gianni Versace. It can't be just Versace."

Mandell works directly with stylists to determine what, in her vintage collection, will suit their client. Then, after a consultation, she allows items to be rented for seven days and also offers "temporary tailoring," to alter a garment's size.

Kourtney Kardashian's stylist Dani Mitchell says she prefers Mandell's collection over others because of their one-of-a-kind nature. "What's so special about Janet's pieces are, besides their label status, their style," Mitchell tells ELLE.com. "Janet has an amazing eye for the most special pieces, and curating a heaven where archives can be accessed. Walking into her showroom takes your breath away... If you love fashion, you need to know about Janet Mandell."

When I ask Mandell what the secret sauce is to sourcing good vintage, plus where to look, she insists her ability to track down unique pieces is genetic: Her mother is a high-end handbags collector, with treasured pieces from Dior, Fendi, and Kieselstein Cord. Her most prized possession, a lizard Kelly bag, is even available to rent at the showroom.

What Mandell will say is that she considers three factors when poking around for fashion finds: label, originality, and, above all, cut.

"It's all about special cuts," she says. "Pieces from the 1990´s and 1980´s had really sexy cuts. Maybe one side is completely open. We have this piece that's sheer and velvet, and it's so low cut that you're able to see a part of your butt in the back. That's just what they did back then! They took risks and today I think Gigi or Bella or Kourtney, any of those girls can rock it. They're not afraid of that."

Mandell opened her first showroom door in Chicago two years ago, and her first call from an A-list client was Gigi Hadid's stylist, Mimi Cuttrell, with a rather unusual request. She wanted an old Balenciaga peacoat to complete Gigi's Mary Poppins costume for Taylor Swift's New Year's Eve bash. "Mimi sent me a picture and was like, "Do you have this?'" says Mandell. "I'm like, 'We do!' and we actually ended up dressing Gigi head-to-toe that night, except the hat."

From then on, calls from celebrity stylists flooded in. She's worked with Monica Rose, who dresses Chrissy Teigen, and Elizabeth Sulcer, Victoria's Secret's go-to stylist. Mandell is also currently collaborating with stylists for both Kim Kardashian and Kylie Jenner.

Because her items are in such high demand, Mandell has the good fortune, she says, of being selective about about what—and to whom—she loans. "If a celebrity stylist calls and they're like, 'What do you have that's vintage?' and I'm not trying to be rude, but I'm like, 'I can't just give a B-list or C-list celebrity this vintage piece,'" she says. "I have to be picky. Like, we have this amazing vintage Versace dress that Elizabeth Hurley wore back in the 1980´s, but I'm not ready to just give it to anybody, because [they have] to be special."