Host and musical guest Justin Timberlake.

Host Seth MacFarlane; Frank Ocean performs "Thinkin' Bout You" and "Pyramids."

Host Martin Short; Paul McCartney performs.

Host Ben Affleck; Kanye West performs.

Bruno Mars hosts and performs "Locked Out of Heaven" and "Young Girls".

Host Anne Hathaway; Rihanna performs "Diamonds" and "Stay".

Host Zach Galifianakis; Of Monsters and Men perform.

Host Kristen Wiig; Vampire Weekend perform.

Host Louis C.K.; Fun performs "Some Nights" and "Carry On".

Host Melissa McCarthy; Phoenix perform.

Host Joseph Gordon-Levitt; Mumford & Sons perform "I Will Wait" and "Below My Feet".

Host Christoph Waltz; Alabama Shakes perform.

Host Christina Applegate; Passion Pit performs "Take a Walk" and "Carried Away."

Host Jeremy Renner; Maroon 5 perform "One More Night" and "Daylight".

Host Jennifer Lawrence; The Lumineers perform.

Host Jamie Foxx; Ne-Yo performs.

Host Adam Levine; Kendrick Lamar performs.

Host Kevin Hart; Macklemore & Ryan Lewis perform.

Host Daniel Craig; Muse perform "Madness" and "Panic Station."

Host Vince Vaughn; Miguel performs.

Host and musical guest Justin Bieber.