Will Ferrell is a famous comedy actor, while Chad Smith is a Rock and Roll Hall of Fame drummer for the Red Hot Chili Peppers. The question posed by many alert fans who've noticed their uncanny resemblance over the years is: Which one is which?

Ferrell joined in the fun last week, claiming to actually BE Smith during a joke-filled Reddit 'Ask Me Anything' session.Smith responded by challenging Ferrell to a drum battle: "His cowbell work is well-documented," Smith said, "but his drumset skills are nominal based on 'Step Brothers' the film."

Ferrell, in turn, has fired back. He suggested they present this mythical standoff -- with drums on one side and cowbell on the other -- as a charity event: "If we can raise $300,000 for Cancer For College," Ferrell countered, "I will face off with you in the greatest drum vs. cowbell showdown the world has ever seen."

Ferrell's challenge was later accepted by Smith - much to the excitement of the lucky charity. No date or venue has yet been chosen, though Ferrell had a suggestion: "We can do it on stage at a Red Hot Chili Peppers concert or in front of a mutually convenient public library."