Leighton Marissa Meester is an American actress and singer. She is known for her starring role as Blair Waldorf on Gossip Girl, which ran from 2007 to 2012. She has also appeared in films such as Killer Movie (2008), Country Strong (2010), The Roommate (2011), Monte Carlo (2011), The Oranges (2011), The Judge (2014), The Weekend Away (2022), and EXmas (2023). She portrayed Angie D'Amato on the ABC sitcom Single Parents (2018–2020). Meester made her Broadway debut in Of Mice and Men (2014).

Blair Cornelia Waldorf is one of the main characters of Gossip Girl, introduced in the original series of novels and also appearing as the lead in the television adaptation; she also appears in the comic adaptation. Described as "a girl of extremes" by creator Cecily von Ziegesar, she is a New York City socialite and a comical overachiever who possesses both snobbish and sensitive sides. Due to her position as queen bee of Manhattan's social scene, Blair's actions and relations are under constant scrutiny from the mysterious Gossip Girl, a popular blogger.