Aziz Ansari hosts the 19th annual bash at the Gibson Amphitheatre in Los Angeles. "The Hangover" leads the pack with six nominations, followed by "New Moon" and "Avatar" with five nods each. Christina Aguilera is scheduled to perform her single "Not Myself Tonight." Presenters include Zac Efron; Bradley Cooper; Cameron Diaz; Jonah Hill; Tom Cruise; Shaun White; and Russell Brand.