Korean superstar PSY teamed up with MC Hammer on Sunday to close out the 2012 American Music Awards with a mash up!  PSY got the audience up and out of their seats and dancing to his international smash hit 'Gangnam Style' and surprised everyone with an appearance from MC Hammer for a mashup of '2 Legit 2 Quit' that really got the crowd going. Check out last night's (Nov 18th) performance right here!