PSY, to no one's surprise, performed his international smash "Gangnam Style" at the 2012 American Music Awards, held on Sunday night (Nov. 18). But the K-Pop star had a special trick up his sleeve: midway through the performance, PSY welcomed MC Hammer onstage, and the pair performed a mash-up of "Gangnam" and the '90s rap star's hit "2 Legit 2 Quit."

As Will.i.am began introducing PSY as the night's final performance, the crowd started cheering and standing up to prepare for the "Gangnam" celebration. The Korean singer was flanked by a handful of dancers as he started singing his No. 2 hit, feverishly dancing in curiously loose-fitting pants.

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Finally, PSY's Hammer pants were greeted by the actual Hammer, who danced vigorously as the "Gangnam Style" horse dance was blended into the "2 Legit 2 Quit" hand gesture. As the performance and AMAs ended, the Nokia Theatre in Los Angeles exploded and watched PSY and MC Hammer panting and smiling next to each other.

The 40th annual American Music Awards also featured performances by Taylor Swift, Nicki Minaj, Usher, No Doubt, Pitbull and Linkin Park, among others. Justin Bieber, who performed "As Long As You Love Me" and "Beauty and a Beat," took home the Artist of the Year trophy.