Leighton Meester in Oscar de la Renta

Shooting Gossip Girl on the streets of New York, Leighton Meester was a veritable Upper East Side princess, wearing an Oscar de la Renta ball gown. With tiers of blush pink silk falling from a bandeau bodice, Leighton topped the fabulous frock with a warm white blazer. The finishing touch? A tiara, of course.