"Hangover" star Zach Galifianakis is in final negotiations to voice the Joker in "Lego Batman", Warner Bros' spin-off of "The Lego Movie". He will join Will Arnett, who is reprising the role of the Caped Crusader he originated in "Lego Movie". Michael Cera recently came on board to voice the hero's sidekick, Robin. Dan Lin, Roy Lee, Phil Lord and Christopher Miller, the custodians of the Lego screen brand, are producing. Chris McKay, the animation supervisor on "Lego Movie", is directing the project, which has a script written by author-screenwriter Seth Grahame-Smith.
