Ricky Gervais Reveals Intimate Fallon Grooming Techniques in 'Lip Flip' Bit

Grand finale finds the duo joining forces for a "Little Drummer Boy" duet

Ricky Gervais is prone to excessive giggling. But Jimmy Fallon's "Lip Flip" game left the comedian cracking up even more than usual during his Tonight Show visit Tuesday night. The bit finds host and guest having their lips digitally swapped during a bizarre conversation, with Gervais' beard imposed on Fallon's freshly shaven mug, and vice versa. Watch the hilarious video above to see Gervais do the Madonna "Vogue" dance and Fallon reveal some intimate grooming techniques.

"What I'd really like to see, honestly, is you interviewing yourself," Fallon says to Gervais to open the clip. The host first gives Gervais a goofy time-share salesman voice, while Gervais makes fun of Fallon for his easy late-night gig ("I'm getting paid now, and someone else is doing all the entertainin'!"). Fallon then makes his guest talk like a baby and stutter through gibberish sentences before Gervais drops some "absolute gospel truth" about the host: "I'm Jimmy Fallon, and I shave my balls." The grand finale is a shockingly in-tune duet of "The Little Drummer Boy."

Monday's installment of the Tonight Show also found Fallon getting silly with a comedy legend. Chris Rock, writer-director-star of Top Five, asked the host to name his five favorite rappers of all-time; Fallon soldiered through the task, naming the Beastie Boys, Jay Z, Run-D.M.C. and Eminem, all of which pleased the rap-obsessed guest. But Fallon's fifth pick was a bit more obscure: He named "Rappin' Duke," referencing Shawn Brown's 1983 novelty track. "Was it between him and [Sir] Mix-a-Lot?" Rock fired back.