Mr. Lagerfeld and his glitter-embossed tuxedo jacket showed up around 8 p.m., trailed by his favorite male model Brad Kroenig and Mr. Kroenig’s children, Hudson, 9, and Jameson, 6.
The model Naomi Campbell moved in for a kiss as Mr. Lagerfeld explained that he was really in town to accept an award from WWD. “I leave Wednesday,” he said.
He, too, loves Ms. Carey, whom he got to know through Mr. Gan, when he photographed her for V in 2006. “I don’t see her in terms of what she likes in fashion,” Mr. Lagerfeld said. “I see her in terms of her personality.”
Naturally, Ms. Carey was last to arrive. After waiters served a salad the size of a postage stamp, Hudson Kroenig was lifted up to the microphone to introduce the night’s special guest.
Then, Ms. Carey walked into the room, dressed in a black satin Chanel trench coat and a sparkly dress, flanked by a couple of security guards. It was tight, but there was no spillage. And it was only 9:30 p.m.
She made her way to the small stage and joined a trio of backup singers. “I just want to hear the music,” she said, as the beat to her 2008 hit “Touch My Body,” kicked in. “Let’s liven things up a little.”
It turned out there was no need for anyone to be nervous. Not as she confidently hit her notes and moved quickly onto other hits, including “We Belong Together” and “Hero,” which she dedicated to Mr. Lagerfeld.
Guests rose from their seats and whooped and hollered. Afterward, she posed for photos with fans. “I’m Gigi,” said Gigi Hadid, who came with her sister, Bella Hadid. “I just want to say hi. You’re amazing.”
It wasn’t entirely clear that Ms. Carey knew who Ms. Hadid was. It wasn’t entirely clear she needed to.
Because of an editing error, an earlier version of this article referred incorrectly to Yolanda Hadid. She is Gigi Hadid’s mother, not her sister.