Leighton Marissa Meester ( LAY-tən; born April 9, 1986) is an American actress, singer, and model. She is known for her starring role as Blair Waldorf on The CW television series Gossip Girl (2007–2012). 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). For her leading role in The CW/Stan comedy drama series Good Cop/Bad Cop (2025), Meester was nominated for the Australian Logie Award for Best Actress.
In addition to acting, Meester has ventured into music. In 2009, she was featured as a guest vocalist on the Cobra Starship single "Good Girls Go Bad", which charted in the top 10 on the Billboard Hot 100. She released solo singles "Somebody to Love" (2009) and "Your Love's a Drug" (2010) on the Universal Republic label. Meester has also recorded songs for various soundtracks. Her debut studio album, Heartstrings, was independently released in 2014. She has also modeled, having been the face of the Jimmy Choo, Herbal Essences, and Vera Wang brands.
