Sarah Lancaster (born February 12, 1980) is an American actress. She is known for her roles of Rachel in Saved by the Bell: The New Class and Madison Kellner on Everwood. She also had a recurring guest role on NBC's Scrubs as JD's love-interest, Lisa the Gift-Shop Girl, and played Marjorie in ABC's TV series What About Brian. In 2005 she starred in the TV movie Living With the Enemy with Mark Humphrey.
Lancaster currently co-stars in the NBC comedy-spy series Chuck, as the title character's sister, Ellie Bartowski and has done so since the show's inception.
Lancaster was born and raised in Overland Park, Kansas, with a younger brother, Daniel. Her parents, Barbara and Michael, were a homemaker and a real estate agent, respectively, before relocating to Mission Viejo, California, where Sarah took up film/TV acting classes with R. J. Adams at The Actors Workshop.
Her skill impressed a talent agent, who helped the then-eighth grader to secure her first series-regular role on Saved by the Bell: The New Class in 1993. During this time, she was tutored on the set and took college courses at the University of California, Irvine to expedite her graduation from high school, after which she moved to Los Angeles to further her acting career.
She has appeared on Sabrina the Teenage Witch, Dawson's Creek, That '70s Show, Scrubs, and CSI: Crime Scene Investigation. She also landed two recurring roles: on The WB series, Everwood, as Ephram's love interest Madison Kellner; and on David E. Kelley's FOX series, Boston Public.
Lancaster has also worked as a jealous girlfriend-turned-serial killer in the movie Lovers Lane, and as the blackjack dealer, Veronica Harold, on CBS's short-lived Dr. Vegas.
Is married to attorney Matthew Jacobs and expecting their first child in the summer of 2011.