Amanda Michelle Seyfried (pronounced /ˈsaɪfrɪd/ "sigh-frid"; born December 3, 1985) is an American actress and former child model. She is best known for her roles as Sophie Sheridan in the feature film Mamma Mia! and as Karen Smith in Mean Girls; she has also appeared in Alpha Dog and in the television shows Veronica Mars, Big Love, and House.
Amanda Seyfried was born in Allentown, Lehigh County, Pennsylvania, United States, the daughter of Ann, an occupational therapist, and Jack Seyfried, a pharmacist. Her sister, Jennifer Seyfried, is a musician in the Philadelphia organ-driven rock band Love City at MySpace. Amanda graduated in 2003 from Allentown's William Allen High School and subsequently enrolled at New York City's Fordham University. As a teenager, she appeared on the cover of three Francine Pascal books. She also sang Thank you for the music at Michael Jackson's memorial concert.
It has been confirmed that since 2008 Amanda has been dating Dominic Cooper, her co-star (and on-sceen fiancee) from Mamma Mia!.
Seyfried started her career as a model at age eleven. From there she went on to acting uncredited in the daytime drama Guiding Light. In 2000, she originated the role of Lucy Montgomery on As the World Turns. From 2002 to 2003, she played the role of Joni Stafford on ABC's All My Children.
In 2004, Seyfried achieved a breakthrough when she was cast as the most dimwitted of the Plastics, Karen Smith, in the popular teen film Mean Girls. In Mean Girls, she initially auditioned for the role of Regina George. She became the original casting choices for both the roles of Regina George and Cady Heron. She was then cast as Regina George's sidekick, and supporting lead, Karen Smith. The other roles later went to Rachel McAdams and Lindsay Lohan, respectively. In 2005, she played the lead character in one of the nine parts in the movie Nine Lives.
Continuing her television career, Seyfried was cast in UPN's Veronica Mars as the title character's murdered best friend Lilly Kane. In her role as Lilly, she appeared on the show through a series of flashbacks, dreams and visions, which portrayed her as a wild, stylish, and bubbly teenage daughter of a business executive. While appearing often during Mars' first season, she also appeared briefly in the second season's premiere and finale. Seyfried originally auditioned for the title role on Veronica Mars, but lost the place to Kristen Bell and she ended up winning the role of Lilly Kane.
Seyfried has had minor guest roles on House, M.D., Justice, Law & Order: Special Victims Unit and CSI: Crime Scene Investigation and as Rebecca on Wildfire. Seyfried also portrays a main character, Sarah Henrickson, in the series Big Love.
She played supporting roles in the 2007 films Alpha Dog and Solstice, and had her first lead role as the bride Sophie in the film version of the musical Mamma Mia!. Her musical performance in that film is also available on Mamma Mia! The Movie Soundtrack. Seyfried recorded a "Gimme! Gimme! Gimme! (A Man After Midnight)" music video specially for Mamma Mia!.
Seyfried joined the cast of the dark horror film Jennifer's Body in February 2008, which began filming in March 2008, playing the title character's best friend. Seyfried has several films in post-production. Titles include "Chloe", "Dear John", and "Boogie Woogie". “Chloe” is a remake of the French film Nathalie, and also stars Liam Neeson and Julianne Moore. Seyfried was scheduled to play the lead in Zack Snyder's new film Sucker Punch, but had to drop out due to scheduling conflicts with Big Love.
She is slotted to star in the both the forthcoming film version of A Woman of No Importance and Gary Winick's Letters To Juliet, which she's shooting in the italian city of Verona, where the tragic story of Romeo and Juliet was set by William Shakespeare.