Jimmy Fallon and Justin Timberlake Unveil HISTORY OF RAP 6

Jimmy Fallon has been the undisputed king of late-night TV since taking the helm of The Tonight Show, but Stephen Colbert's debut as host of The Late Show must be seen by NBC has a severe enough threat to roll out a big gun: Justin Timberlake.

Timberlake joined his buddy for Thursday night's episode of The Tonight Show, unveiling "History of Rap 6," the latest installment in the duo's long-running musical medley series.



Fallon and Colbert are very different hosts, and while the two are friendly with each other, their networks are treating this new rivalry as something serious. You don't start an episode of The Tonight Show with a six-minute Timberlake segment if you aren't trying to keep people from changing the channel to Colbert's The Late Show.