Leighton Marissa Claire Meester (born April 9, 1986) is an American actress and aspiring singer and songwriter, best known for her role as Blair Waldorf in the TV series Gossip Girl. His first role in a TV show was on NBC's legal drama Law & Order in 1999. Other series in which Meester has appeared include surface, Entourage, CSI: Miami, 8 Simple Rules, 24, 7th Heaven, and House.