Olivia Olson

Olivia Olson (born May 21, 1992) is an American actress and singer-songwriter. She is known for her role of Joanna, singing "All I Want For Christmas Is You", in Love Actually (2003) and for her voice-roles as Vanessa Doofenshmirtz in Phineas and Ferb and as Marceline the Vampire Queen in Adventure Time with Finn and Jake.

Personal
Olson was adopted at birth and raised in Los Angeles, California. She lives with her mother, brother and father who is comedy writer, Martin Olson. Her birth father is Rasta poet/musician Hendy Foote.

Career
She has appeared as a singer and actress on many television shows and has performed live in many Hollywood theaters, including Comedy Central Stage, the HBO Theater, The Fake Gallery, and The Disney TV show Phineas and Ferb. Olson has also appeared on The Tracy Morgan Show and was guest starred on The Ellen DeGeneres Show singing with DeGeneres and actor Jack Black. According to director Richard Curtis' commentary in the music section of the Love Actually DVD, Olson's singing was so perfect, they were afraid the audience would not believe that a ten-year-old could really sing the way she did. They had to train her so that her singing would sound more believable.

She was a cast member and singer on two animated series: Cartoon Network's series "Adventure Time!", playing Marcelline the Vampire, and on Disney's animated series Phineas and Ferb playing Vanessa Doofenshmirtz, the sarcastic daughter of the evil Dr. Doofenshmirtz. She also sang some songs in this Disney series, including the duet "Busted!" with Ashley Tisdale as well as solo songs, including "I'm Me," "Not So Bad A Dad After All," "I'm Lindana and I Wanna Have Fun", and her song in the special "Phineas and Ferb Christmas Vacation", "Got That Christmas Feeling." Still in her teens, she has written songs for Phineas and Ferb, and has written and recorded her own songs with renowned music producers Rick Nowels, Camara Kambon and Hollywood jazz great Rob Mullins.