Hynden Walch

Heidi Hynden Walch (born February 1, 1971) is an American voice actor, best known for playing Starfire (as well as her sister Blackfire) on Teen Titans and Princess Bubblegum on Adventure Time. She also alternates with Tara Strong as the current voice of Harley Quinn in all Batman and DC Comics media. She is also known for voicing young Nia on Gurren Lagann, Breach on Generator Rex and Viridi in Kid Icarus: Uprising.

Oh, and she's in Groundhog Day!