Read about how it came together: Too Legit To Gangnam Style: How The Amazing Hammer/PSY Duo Was Born At Google Zeitgeist:
Scooter Braun, who’s PSY’s agent (as well as Justin Beibers’s), was apparently hanging out with super angel Ron Conway, MC Hammer and others at the Google event. Braun mentioned to Hammer that PSY was a huge fan of Hammer’s and had expressed an interest in bringing Hammer on stage at the AMA to perform with him.
Hammer agreed. Scooter then handed Hammer his cell phone, which was ringing to an outbound phone. PSY picked up and the details were arranged.
Image: 2012 American Music Awards Crowd Goes Crazy. Courtesy ABC
Image: Steve Garfield and MC Hammer at Gravity Summit