[VIDEO] Macklemore & Ryan Lewis Perform on Letterman

Macklemore & Ryan Lewis performed their next single off their album "The Heist" called "Can't Hold Us" Ft. Ray Dalton. David Letterman had a hard time remembering Ryan Lewis's name or even knowing who he is after the performance ends. Pretty funny stuff. Shouldn't David Letterman know who his guests are before they perform? Watch and let me know what you think? -- Maynard