Olivia Olson

Olson's latest album Nowhere Land was released on June 22, 2018. She worked with K-pop producers Kairos Music Group and producer/singer/songwriter John Defeo on the project. In October 2019, she began competing in The X Factor: Celebrity, being the second act to be evicted from the live shows on October 26, 2019.

In 2015 Olivia and her father Martin Olson co-authored a novel for the series, Adventure Time's: The Enchiridion & Marcy's Super Secret Scrapbook. Olivia wrote her section in first person as her character Marceline. The book was illustrated by artists including Tony Millionaire, Renee French, Celeste Moreno and Sean Tejaratchi.

She frequently posts original music on her YouTube account Olivia Olson. On July 18, 2013, Olson released her debut EP Beauty Is Chaos. Olson has also performed the song "Haven't You Noticed (I'm a Star)", which was featured on the September 17, 2015 episode of Steven Universe entitled "Sadie's Song". It was later featured in the Steven Universe mini-episode "Gem Karaoke", released on October 3, 2016. She appears at Comic-Cons and pop conventions around the world with other cast members from her shows.

In 2010, Olson got the role of Marceline the Vampire Queen on the animated Cartoon Network series Adventure Time. The series has been a commercial and popular success and her character is one of the most popular ones. Her character is similar to that of Vanessa on Phineas and Ferb, in which she has problems with her evil father, along with their dark personalities. Marceline is a fun-loving, mischief-seeking 1,005-year-old vampire who looks like a teenager. She has an involved back story that is explored throughout the show. She first appeared as an antagonist, but later appears to be the main characters' (Finn and Jake's) friend. Like Phineas and Ferb, she sings often on the show, including the popular song "The Fry Song", in which she sings about her father eating her fries and how sad she is, even though it is something much deeper. In the Adventure Time mini-series "Stakes", Olson performs the popular song "Everything Stays", which was revealed by Olson and Rebecca Sugar at the 2015 San Diego Comic-Con. Her character has become popular with fans and there is a wide range of Marceline products available, such as shirts, action figures, key chains, plushes, wallets, belts, necklaces and bracelets, etc.

From 2008 to 2015, Olson voiced the recurring character Vanessa Doofenshmirtz in the Disney animated series Phineas and Ferb along with actor Thomas Sangster (Ferb Fletcher), who played Joanna's love interest Sam in Love Actually. Her character is described as a punk goth, the sarcastic daughter of the not-so-evil Dr. Doofenshmirtz. She occasionally attempts to thwart her father's evil schemes regarding her mother, always ending in failure. Although she is a sarcastic and spoiled teenager, she also has a kind heart and loves her parents. Olson's father, Martin, was a head writer for the first season of the show, and one of the main songwriters at Disney throughout the series.

Olson rose to fame for her role as Joanna Anderson in the 2003 holiday film Love Actually, singing the song "All I Want for Christmas Is You". Her singing was praised, with director Richard Curtis stating in the commentary in the music section of the Love Actually DVD that 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 and would assume she was lip-synching to Mariah Carey's voice. They had to train her so her singing would sound more believable, and add the sounds of inhalations to the track. This led to guest spots on The Ellen Show, The Tracy Morgan Show and singing with Jack Black and Kristin Chenoweth. Olson also posted original songs on her YouTube account.

Olivia Rose Olson (born May 21, 1992) is an American actress and singer-songwriter, mostly 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.