Olivia Olson (born May 21, 1992) is an American actress, singer-songwriter, and writer, largely known for her voice roles as Vanessa Doofenshmirtz in Phineas and Ferb and Marceline the Vampire Queen in Adventure Time.

She also played the character of Joanna in the 2003 film Love Actually and its 2017 short sequel Red Nose Day Actually.

[1] Olson has appeared as a singer and actress on television shows and in live theatre, including Comedy Central Stage, the HBO Theater, and The Fake Gallery.

Olson moved into the mainstream with her role as Joanna Anderson in the 2003 holiday film Love Actually, singing the song "All I Want for Christmas Is You".

In 2017, Olson reprised her role as Joanna in Red Nose Day Actually, a short film which is a sequel to Love Actually.

[8] In 2011, Olson voiced Vanessa in a deleted scene of Phineas and Ferb the Movie: Across the 2nd Dimension, which included a musical number, but sang a song for the film "I Walk Away".

[9] In 2010, Olson got the role of Marceline the Vampire Queen on the animated Cartoon Network series Adventure Time.

[13] In the series, Olson also sings Marceline's songs, which were written by storyboard artists, or other people affiliated with production.

The book was illustrated by artists including Mahendra Singh, Tony Millionaire, Renee French, Celeste Moreno and Sean Tejaratchi.

[29] From 2016 to 2019, Olivia voiced the fourth Powerpuff Girl Bliss on Cartoon Network's reboot of The Powerpuff Girls,[30][31] The character's initial announcement was met with negative reactions from some fans,[32][33] but when rumors began to spread that the character would be black, fans began to express a more optimistic tone.

[34] Reviewers later called the character a great step forward in terms of racial diversity and a good addition.