Watch Casey Abrams & Jack Black Get Down To 'Fat Bottomed Girls' on 'American Idol'

The star-studded finale of American Idol season 10 certainly had some big surprises. Casey Abrams took the stage, and to the delight of the audience, was joined by funnyman Jack Black for a hip-gyrating performance of Queen's mega-hit "Fat Bottomed Girls."

Jack is no stranger to the music world — getting his first big break as half of the musical duo Tenacious D.  Their rendition of "Fat Bottomed Girls" was silly and tons of fun.

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It must have been a magical moment for Casey, who told OK! during his visit last month that Jack was one of the stars he would love to collaborate with!

"I think it would be weird to collaborate with Ke$ha. I think something along those lines. I’d like to collaborate with Esperanza Spalding, Jack Black and some jazz musicians that are very obscure," Casey told OK!.

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Catch the clip, below!