Hey, remember Joanna from the movie "Love Actually"?
The girl that Sam is in love with?
She is the voice of Marceline on "Adventure Time."
Yes, the girl who sings "All I Want for Christmas Is You."
She grew up to voice Marceline.
Yup, THAT Marceline.
The Finn-loving vampire queen.
(They even have a similar kissing technique?)
(Her real name is Olivia Olson.)
(And she voices Marceline.)
DID THAT JUST BLOW YOUR MIND?
UPDATE: Cole Sanchez, Adventure Time artist and writer has informed us that Olivia's father, Martin Olson, voices Marceline's father on the show as well!