Justin Bieber, Katy Perry & Jennifer Lopez Rock the House at 2011 American Music Awards

By Sadie Gennis

Photography by: Kevork Djansezian/Getty Images

David Hasselhoff, SkyBlu and Redfoo Nov. 20

David Hasselhoff performs with singers SkyBlu and Redfoo of LMFAO onstage at the 2011 American Music Awards held at Nokia Theatre in L.A. on Nov. 20.

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L.A.'s Nokia Theatre was bursting with star power Sunday night.

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The 2011 American Music Awards included a number of powerhouse performances by Jennifer Lopez, Katy Perry, Nicki Minaj, Drake and more.

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Some of the most memorable moments of the evening were thanks to "Party Rock Anthem" singers LMFAO, who were joined onstage by Justin Bieber and a pants-less David Hasselhoff.