Jimmy Fallon's 'Tonight Show' already has the best drums in late night courtesy of the Roots' Questlove, but on May 22, the show will be even more beat-heavy than usual, courtesy of what promises to be an epic drum battle between Chad Smith and Will Ferrell.

The tongue-in-cheek throwdown, which is being held as a fundraiser for the charities Cancer for College and Little Kids Rock, was inspired by Smith and Ferrell's oft-noted physical resemblance, which reached a head earlier this year when Smith told Ferrell to stop impersonating him and challenged him to a faceoff behind the kit. "We're going to have a drum-off to see who the real Chad Smith is," Smith told Rolling Stone. "I'm all for it. But unless Will's been practicing or is secretly a crazy, wild drummer, I think it'll be evident right off the bat who the real Chad Smith is. I'm ready to take him down."

"I have not been practicing," Ferrell responded. "There's no amount of practice that would help me become a good drummer."

Of course, what Ferrell lacks in actual technical skill, he can always try to make up with his trademark overbearing chutzpah -- something Smith admitted he's worried about when he referenced the classic 'SNL' skit that found Ferrell whacking on a cowbell as (fictional) Blue Oyster Cult percussionist Gene Frenkle. "I believe they'll be some cowbell involved," he sighed. "And that's what worries me. He might try to win everybody over with his whole cowbell thing. I might have to wrestle and tackle him."

"It's going to end in a way that will be extremely surprising to the audience," predicted Ferrell. "It may be something too powerful for the audience to even handle, so it may just be an one-time event. Man only went to the moon once, right? But it could become the beginning of a rivalry that will go on until the end of time."

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