Justin Timberlake and Jimmy Fallon Debut 'History of Rap 5'

After canceling one show earlier in the week due to illness, Justin Timberlake got back to business, helping his pal Jimmy Fallon close out his debut week as “Tonight Show” host. The pop crooner served as guest, performer, and wingman to Jimmy, debuting the fifth installment in their famous “History of Rap” series.

With some help from The Roots, the dynamic duo rapped along to a new crop of hip-hop classics including the Notorious B.I.G.’s “Big Poppa,” Kris Kross’ “Jump,” Jay Z’s “99 Problems,” Drake’s “Started From the Bottom,” and Kanye West’s “Good Life,” ending with Run-DMC and Aerosmith’s “Walk This Way.”

JT also grabbed his guitar and performed “Not a Bad Thing” with his band, JT & the Tennessee Kids.

His “20/20 Experience World Tour” continues Monday in Washington, D.C.

Watch their rap session below.