Leighton Meester is a person.
Leighton Marissa Meester ( born April 9 , 1986 ) is an American actress , singer-songwriter and model . She is mostly known for her starring role as Blair Waldorf in the drama series Gossip Girl ( 2007 -- 2012 ) . She has also appeared in the films Killer Movie ( 2008 ) , Country Strong ( 2010 ) , The Roommate ( 2011 ) , Monte Carlo ( 2011 ) , The Oranges ( 2011 ) , and The Judge ( 2014 ) . In addition to acting , Meester has also ventured into music .