House of Mouse Expo Welcomes Olivia Olson. Olivia Olson is an American actress, singer-songwriter, and screenwriter, 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.
Along with this, she is also a writer, having written the Boom! Studios graphic novel Marcy and Simon, co-authored Adventure Time: The Enchiridion and Marcy’s Super-Secret Scrapbook, and contributed writing to the best-seller Adventure Time Encyclopedia for Cartoon Network. In 2023, she began writing for the Phineas and Ferbrevival.
Olivia Olson has built a dynamic career as both a singer and actress, moving seamlessly between live theatre, television, film, and some of the most beloved animated series of the past two decades. From early stage performances at Comedy Central Stage and the HBO Theater to global recognition in a holiday classic, Olson’s journey is as impressive as it is multifaceted.
Olson first stepped into the spotlight as Joanna Anderson in the 2003 holiday film Love Actually. Her unforgettable performance of “All I Want for Christmas Is You” instantly became one of the film’s most iconic moments. Director Richard Curtis even shared that her vocals were so flawless, the production team worried audiences wouldn’t believe a 10-year-old could sing that well. To make the performance feel more authentic, subtle breathing sounds were added to the track.
The film’s success opened doors to appearances on talk shows such as The Ellen Show and The Tracy Morgan Show, along with musical collaborations with stars like Jack Black and Kristin Chenoweth. Olson later reprised her role as Joanna in the 2017 sequel short, Red Nose Day Actually, bringing nostalgic joy to longtime fans.
From 2008 through 2015, Olson voiced Vanessa Doofenshmirtz on Disney’s hit animated series Phineas and Ferb. Her character quickly became a fan favorite, thanks in part to Olson’s standout musical performances. She delivered memorable songs including the popular duet “Busted!” alongside Ashley Tisdale, as well as solos like “I’m Me,” “Not So Bad a Dad,” and “Got That Christmas Feeling.”
Beyond voice acting, Olson also contributed creatively behind the scenes, writing and recording original music with respected producers. She even voiced Vanessa in Phineas and Ferb the Movie: Across the 2nd Dimension, performing the song “I Walk Away.”
Olson’s role as Vanessa paved the way for another career-defining part: Marceline the Vampire Queen on Cartoon Network’s Adventure Time. Originally auditioning for Princess Bubblegum, Olson ultimately landed the role of Marceline — a character that would become one of the show’s most beloved figures.
Marceline’s emotional depth and musical performances helped elevate the series, with Olson performing many of the character’s most memorable songs. “Everything Stays,” introduced during the mini-series “Stakes,” remains a fan-favorite anthem years later. Critics praised Marceline not only as a character but as a cultural touchpoint, often citing her songs as among the best in the series.
In 2015, Olson co-authored Adventure Time: The Enchiridion & Marcy’s Super Secret Scrapbook with her father, Martin Olson, writing her portions in Marceline’s voice. She later reprised the character in Adventure Time: Distant Lands (2020–2021) and again in Adventure Time: Fionna and Cake (2023), further cementing Marceline’s lasting impact.
Olson’s animated résumé continued to grow with roles in Steven Universe, where she performed “Haven’t You Noticed (I’m a Star),” and as Bliss, the fourth Powerpuff Girl, in Cartoon Network’s reboot of The Powerpuff Girls. While Bliss sparked online debate at her introduction, many critics later praised the character as an important step forward in diversity and representation.
She also voiced characters in Fast & Furious: Spy Racers and reprised Vanessa Doofenshmirtz in Phineas and Ferb the Movie: Candace Against the Universe (2020). In exciting news for longtime fans, Olson was later confirmed not only to return as Vanessa in the Phineas and Ferb revival, but also to serve as a writer on the series — showcasing her evolution from performer to creative contributor.
Outside of animation, Olson has continued building her music career. She released her debut EP Beauty Is Chaos in 2013 and followed it with the album Nowhere Land in 2018, collaborating with international producers and songwriters. She also competed on The X Factor: Celebrity in 2019, bringing her powerhouse vocals to a new audience.
Olson shares original music with fans across platforms like YouTube and TikTok, continuing to connect with audiences worldwide through both nostalgia and new creative ventures.
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