This is the best "Lip Flip" yet!

Ricky Gervais stopped by "The Tonight Show" on Tuesday night, where he swapped mouths with Jimmy Fallon and had the late night host cracking up with his raunchy antics.

The best part? Both adopted Southern accents in order to speak like the other comedian!

"Hi, I'm Jimmy Fallon—I got my own TV show," said Jimmy—well, said Ricky as Jimmy. "Yeah, I can't believe it neither! I come on and I sit down and I talk, and sometimes I sing, and other people talk, and when other people are talking I'm getting paid when they're talking! It's amazing! I'm getting paid now and someone else is doing all the entertaining!"

After Jimmy made Ricky call himself a "little baby," Ricky pulled out the big guns by telling "the absolute truth" about Jimmy's personal grooming habits (Hint: it involves his balls!)

Check out the hilarious clip above to hear them sing a duet of "The Little Drummer Boy," and click "Launch Gallery" at the top to see more late-night highlights.