LEONARD’S BIG NIGHT: Leonard Lauder, the chairman emeritus of the Estée Lauder Cos., hosted his closest friends, family and colleagues, plus a handful of beauty editors, in sipping Champagne after hours in the foyer of the Met Breuer on New York’s Upper East Side on Monday. The crowd was celebrating the museum’s reopening as a new part of the Met (as well as William Lauder’s 56th birthday).

“You are standing now in a time capsule, because this is exactly the way this room looked when it was opened in 1966 — everything — the lighting, the walls,” Leonard Lauder told guests. “You will see that all of the original names of the donors are still on the wall…including mine.”

The revamping process started in 2010 when the Whitney’s move left the Breuer building’s future up in the air. “I got very tense, because this is my place,” Lauder said. So he worked to fix the building up with a new facade and started talks to house part of the Metropolitan Museum’s contemporary collection during Met renovations, he said.

After cocktails, guests meandered through the building’s two exhibits: one showcases the art of India’s Nasreen Mohamedi through June 5, and another — “Unfinished” — presents 197 works that call into question the point at which a piece of art is complete. The presentation aims to leave visitors with insight into the creative processes of a wide range of artists, not just contemporary ones, through viewing pieces that either were not finished, or were left to look incomplete. Works from Leonardo Da Vinci, Picasso, Andy Warhol, Rembrandt, Michelangelo, Vincent van Gogh, Manet, James Drummond, Jackson Pollock, George Brecht, Jasper Johns, Piet Mondrian, Willem de Kooning, Cy Twombly and lots of others are on display through Sept. 4.