Leighton Meester Flashes Booty, Bad Fashion Sense

11/17/2010 9:45 AM PST
Having apparently lost some sort of bet, "Gossip Girl" star Leighton Meester showed up to an event in NYC last night leaving little to the imagination ... by wearing an unfortunate lacy sheer butt-flashing genie pant one-piece jumper thing.

Blair Waldorf is not going to be happy about this.