Tina Fey, Jimmy Fallon

Tina Fey and Jimmy Fallon used to share a desk for SNL's "Weekend Update," but on Monday's Tonight Show the pair shared mouths.

It all started when Fey gave voice to our dreams, telling Fallon she wanted to shake things up: "You're doing a pretty good job, but I would also like to interview me." Fallon didn't hesitate before granting Fey's wish, launching into a "Lip Flip" bit, in which the duo's mouths are imposed on each other's faces.

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After engaging in brief rapport and fake vomiting, Fallon asked Fey, "I heard you like to sing, is that true?" And so began the only cover of "Endless Love" that ever need exist.