Justin Timberlake, Jimmy Fallon and The Roots Perform "A History of Rap"

When Late Night airs later on this evening, Justin Timberlake, Jimmy Fallon, and The Roots will perform a pretty fantastic medley of famous rappers. Catch the song (which features impersonations from Snoop Dogg to Eminem) early behind the cut!

(Apparently, NBC's embeddable video looks funky when viewed with certain browsers. Click here to watch an alternate version.)