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Obsessed with Gaga's golden headpiece.
Mother Monster's hiding place for much of the evening.
Gaga, sound asleep.
Good morning, sunshine!
Olivier Theyskens—who fashioned his mask out of the party invite!—and Jessica Stam.
Photographer/director Steven Klein.
Hi, Lindsay Lohan!
A devilish-looking Marc Jacobs.
Paris Hilton stopped by.
As did Charlotte Ronson, wearing an awesome Maison Michel lace hat.
Alexandra Richards chose a beaded mask.
Yoko Ono in full Mad Hatter mode.