Attention Upper East Siders: there was a secret debutante ball happening at the Plaza Hotel last night and it was more fun than we could ever imagine. Starring Betsey Johnson and her Spring 2010 collection, the party marked the "coming out" of over 50 BJ outfits, plus a first-time runway appearance by Georgia May Jagger and a performance by indie rock darling Ida Maria. When she started playing her hit, "I like you so much better when you're naked," model Darla Baker went crazy and led the audience in a massive dance party. Fortunately, all the (fabulous, sparkly, '80s flashback) clothes stayed on!