Stefani and Shelton score major laughs with Fallon's 'Lip Sync Battle'

Oh, that Jimmy Fallon. He's such a kidder with the best gags. And, what's even better is that he gets some of the biggest stars in the world to participate in his silliness.

He played another round of "Lip Sync Battle" this week and the participants were none other than The Voice's Gwen Stefani and Blake Shelton.

Shelton kicked things off with an LOL version of Puttin' on the Ritz, and Stefani did a rendition of Call Me Maybe.

But the real killer was their duet of Endless Love. SO FUNNY.