Mischa Anne Marsden Barton (born 24 January 1986) is a British-American fashion model, film, television, and stage actress. She began her acting career on the stage, appearing in Tony Kushner's Slavs! and took the lead in James Lapine's Twelve Dreams at New York's Lincoln Center. She made her screen debut, making a guest appearance on the American soap opera All My Children (1996). She then voiced a character on KaBlam! (1996-1997), an animated television series on Nickelodeon. Her first major film role was as the protagonist of Lawn Dogs (1997), an acclaimed drama co-starring Sam Rockwell. She continued acting, appearing in major box office pictures such as the romantic comedy, Notting Hill (1999) and M. Night Shyamalan's psychological thriller, The Sixth Sense (1999).
She later appeared in the independent drama, Lost and Delirious (2001) and played Evan Rachel Wood's girlfriend during a guest-arc on ABC's Once and Again (2001-2002). She is best known for her role as Marissa Cooper in the Fox television series The O.C. (2003-2006), for which she received two Teen Choice Awards and a Prism Award nomination. Entertainment Weekly named her the "It Girl" of 2003.
She has since appeared in the comedy remake St Trinian's (2007) and the Richard Attenborough-directed drama Closing the Ring (2007). She also starred in the neo noir comedy, Assassination of a High School President (2008), the Roland Joffé drama, You and I (2008) and the horror Homecoming (2009). She returned to television, starring in the short-lived Ashton Kutcher-produced CW series, The Beautiful Life: TBL (2009) and made a guest-appearance in Law & Order: Special Victims Unit (2010). Her upcoming releases include the historical drama, Bhopal: Prayer for Rain and the horror remake, Apartment 1303 3D.