NBC/The Tonight Show With Jimmy Fallon

Watch Will Ferrell's Epic 'Tonight Show' Drum-Off

More cowbell, please.

The time for talking was over. It was time to get on that stool and crush it. Okay, first there was some more talking, then the crushing.

After months of hype, Will Ferrell and Red Hot Chili Peppers drummer (and doppelganger) Chad Smith finally sat down together on "The Tonight Show" on Thursday night to determine who is the greatest drummer of all time. Dressed identically in jeans, black leather jackets, Kiss t-shirts and backwards baseball caps (so, basically like Smith every day), at first they both pretended to be the other guy.

"He's an imposter," Smith (as Ferrell) said to host Jimmy Fallon, explaining that Chad Smith is a character he, Will Ferrell, created. Wait, what? That led to the real Chad Smith (aka Ferrell) describe how pissed he was to hear such falsehoods and recalling the first time he heard the slander.

"Yeah, I was jammin'," said Ferrell (the real one, we think). "I was jammin' with the Chili Peppers, my guys, at our jam house." The gag went on for a bit, but we won't bore you with that. Let's get to jam that benefitted Smith's charity, Little Kids Rock and Ferrell's, Cancer for College.

And watch out for the special guest stars who come out near the end for a wicked cowbell-assisted throwdown.