I'm not internationally known, but I'm known to rock a microphone!

"You're a famous rapper, and I'm a classically trained beatboxer, so I want to try something fun with you here," Fallon tells Smith. Using a beatbox iPad app that layers and loops vocal tracks, Smith and Fallon build the song from the drum breaks up, ultimately taking their creation to the Tonight Show stage where the Roots add their own instrumentation to the 1988 single. This isn't the first time Fallon has busted out this music app: Last year, he and Billy Joel put their vocal powers on display with a doo-wop cover of "The Lion Sleeps Tonight."

Ever since The Tonight Show arrived back in Los Angeles on Monday, the stomping ground of previous hosts Johnny Carson and Jay Leno, it's been a nostalgic look back at the early Nineties as Fallon recreated The Fresh Prince of Bel Air opening and reunited with most of the Saved By the Bell cast in the halls of Bayside High. The L.A. visit also found Neil Young performing "Old Man" with "Neil Young."

Haha, this is worth watching again too.