Listen to Mark Hamill do the voice of The Joker one more time along with Tara Strong as Harley Quinn in the following video.
We also just heard Mark Hamill's The Joker from Batman: The Animated Series do the Emperor in Star Wars as well as giving his Heath Ledger impression for "Why so serious?"
Mark Hamill has voiced The Joker many times including for Superman: The Animated Series, Justice League and the Batman Arkham video games.
Hamill is also thought to be returning for Star Wars: Episode VII in 2015 reprising as Luke Skywalker.
Tara Strong is the voice of Harley Quinn in the new Injustice: Gods Among Us video game as well as having voiced the character in Batman: Arkham City.