Nick Gruber was treated to a balloon-filled, late-night 21st-birthday party at Indochine, courtesy of boyfriend Calvin Klein on Friday night. Party planner Bronson Van Wyck created a Studio 54-meets-New Year’s Eve dinner party at Indochine, stocked with 4,500 balloons, 100 models and a cake with 21 sparklers on top. Fashion’s elite including Anna Wintour, Steven Klein, Patrick McCarthy, Donna Karan, Daphne Guinness, Ingrid Sischy, Sandy Brant and Vera Wang partied with Evan Lysacek, Andy Cohen, Ian Schrager and 150 or so more. Wang and Lysacek were the first ones on the dance floor, while Guinness took in the scene from her perch on the back of a banquette. The crew kept the lights on well past 3 a.m. “It was so hot inside, we had to open the doors to the outside for air and have the waiters pass iced tequila shots,” said an attendee.