Funnyman Will Ferrell and Red Hot Chili Peppers drummer Chad Smith faced battle in a drum-off for charity.

Funnyman Will Ferrell and Red Hot Chili Peppers drummer Chad Smith faced battle in a drum-off for charity.

Drop everything. The greatest moment in the history of television has finally happened.

Will Ferrell and his uncanny doppelganger Chad Smith, the Red Hot Chili Peppers’ drummer, fronted up on The Tonight Show with Jimmy Fallon for a much-touted drum-off. 

The stunt, which raised cash for charity, also saw the full Chili Peppers line-up join the stage to blast out a version of (Don’t Fear) The Reaper by Blue Oyster Cult.

Will Ferrell and Chad Smith appeared on The Tonight Show with Jimmy Fallon.

Will Ferrell and Chad Smith appeared on The Tonight Show with Jimmy Fallon.

The drum-off was sparked in February when, during a Chad Smith Reddit AMA, Ferrell challenged Smith to a drum battle in the name of charity. 

Responding in the AMA, Smith said: ‘‘Tell Will Ferrell anytime, anyplace, I'll take him down. I don't want to embarrass him, but I'd say don't bring your family. Especially children. I don't want them to see this.’’

Swapping more trash talk on the show, the drum-off was eventually won by Ferrell, who trumped the Chili Peppers’s drummer with his cowbell skills. The cowbell reference goes way back in Saturday Night Live history in a skit from 2000 which features the catchphrase "more cowbell" where Ferrell plays musician Gene Finkle who performs on (Don’t Fear) The Reaper.  

On Fallon's show, which aired Thursday night in the US, the incredible resemblance between the pair was amplified by the fact they wore the same outfit of a backwards baseball cap, black Kiss T-shirts, leather jackets and jeans. Sitting next to each other on the sofa next to host Fallon, the pair looked like a couple of clones. 

The duo had a short chat with Fallon during which they both pretended to be each other. 

‘‘Anyway, enough small talk,’’ said Fallon. ‘‘You can feel the energy in the air. You know what the audience, wants, you know what I want. You know what America wants. It’s time to find out once and for all, who’s the better drummer?’’

Playing four solos each, with Ferrell clearly miming, the pair traded insults. ‘‘That was cute,’’ mocked Ferrell. ‘‘Do you play for the lukewarm Chili Peppers?’’

Eventually Ferrell took up the cowbell before the rest of Smith’s bandmates rushed the stage in the shape of Anthony Kiedis, Flea and Josh Klinghoffer to perform the Blue Oyster Cult Classic. 

The pair raised money for charities Cancer for College and Little Kids Rock. 

In behind-the-scenes footage posted on funnyordie.com, Ferrell said Smith had come off stage and cried. 

‘‘I know the term like a little girl is overused, but he literally cried like a little girl.’’