Olivia Olson is an American singer and actress. She was the original singer of "Haven't You Noticed (I'm a Star)".
She voices Vanessa Doofenshmirtz in Disney's Phineas and Ferb, and Marceline Abadeer in the Cartoon Network series Adventure Time. She also played Joanna in the film Love Actually and its sequel, Red Nose Day Actually.
- She was the first voice actress whose character doesn't physically appear on the show (excluding the photo on the CD) and didn't have any non-singing speaking lines, the second was Emily King.
- The woman on the CD resembles Vanessa from Phineas and Ferb, and Marceline from Adventure Time, both voiced by Olivia.