K A T I E   H O L M E S :
The Girl Next Door

Katie Holmes, Sienna Miller, and More Lavishly Celebrate Cartier's New Fifth Avenue Mansion During NYFW

By Jonathan Borge

You know it'll be a grand time when it's impossible not to turn the corner and find a Champagne bar.

That's how Cartier celebrated its newly-minted Fifth Avenue mansion in New York City Wednesday night, showing off a polished look after a two-and-a-half year renovation. "What happened to the air conditioning?" Orange Is the New Black star Taylor Schilling jokingly asked as she entered an elevator and made her way through the venue's six opulent floors. Sure, the space may have been filled to the brim with stars like Schilling, Katie Holmes (with her mom), Chloe Gracë Moretz, Jourdan Dunn, Sienna Miller, Rooney Mara, and Sofia Coppola, to name a few, but a tight squeeze didn't stop everyone from gawking over the fine jewels on display.

"There's not one part that didn't make my jaw drop. These diamonds are incredible, really incredible," Holmes, dressed in Valentino, told InStyle about her reaction to the space. "I feel so honored to be here ... I really enjoyed walking around and seeing all of the pieces, seeing Grace Kelly's old pieces. I just played Jackie Kennedy [in a new flick], so Cartier means a lot to her."

While diamonds by far proved to be a girl's best friend—hits included the Princess Grace Suite dedicated to Kelly and a separate room with Elizabeth Taylor's beloved pieces—other lavish attractions kept guests busy. Moretz and Mara spent time relaxing with friends, respectively, on plush white couches on the sixth floor, where an open-air courtyard and live DJ made for plenty of dancing.

Meanwhile, Tavi Gevinson and A-listers like Olivia Palermo and hubby Johannes Huebl made their way from suite to suite, some of which were transformed into full-room photo booths with gilded detailing. Dunn and model BFF Hailey Clauson hung out on the first floor, enjoying a live performance by Kacy Hill, who glamorously belted it out atop a moving swing. Later, the New York City Ballet impressed crowds with a dazzling display inside the Princess Grace Salon, naturally.

So did the handsome, suspender-clad wait staff, serving caviar and bedazzled jewels, keep everyone inside the mansion? Not so much. Following cocktail hour, the party kept going across Fifth Avenue—staff dressed as Cartier bellmen blocked off the crosswalk for easy access—where the brand transformed an open space into a house replete with a kitchen, living room, dance floor, and artsy open spaces.

Fashion icon Iris Apfel was also in attendance, while other revelers were attracted by an Instagram opportunity inside what looked to be a bathroom. An oversize bathtub sat beneath a light fixture designed to look like a showerhead. Larger-than-life stacked plates gave the space an Alice in Wonderland effect while a gilded grilled cheese station (they were pressed with an iron) caught everyone's eye.

The most impressive? Beyoncé-approved duo Chloe and Halle took the stage to everyone’s delight and were later followed by surprise performer Ellie Goulding and man of the hour, Questlove.

Way to kick off fashion week, Cartier.