Watch Amy Schumer, Jennifer Lawrence Dance Atop Billy Joel's Piano

Actresses reenact 'Trainwreck' "Uptown Girl" dance sequence at Wrigley Field concert

Amy Schumer and Jennifer Lawrence, screenwriting tandem and budding best friends, made a surprise appearance during Billy Joel's Wrigley Field concert in Chicago Thursday night to lead an onstage dance party during "Uptown Girl." As video from the performance shows, Schumer was the first one out to dance during Joel's 1983 single before being joined onstage by a group of friends that included Lawrence. The two actresses then hopped atop Joel's piano for the remainder of the song as the vocalist serenaded them.

Spoiler alert: The impromptu appearance doubled as a nod to the dance sequence at the end of Schumer's comedy Trainwreck, where the actress dances to "Uptown Girl" along with the New York Knicks cheerleaders at Madison Square Garden. Schumer happened to be in Chicago for the Windy City stop of the Oddball Festival, giving the comedian and Lawrence an opportunity to bring that fictitious dance scene to reality.

Lawrence and Schumer, who became fast friends after meeting in July, are already at work co-writing a screenplay in which they will portray sisters. "We're almost done writing. It just flowed out of us. We've got about 100 pages right now," Lawrence said of the comedy. "Amy and I were creatively made for each other. We have different flavors. It's been the most fun experience of my life. We start the day off on the phone, laughing. And then we send each other pages. And we crack up. I'm flying out tomorrow to see her in Chicago," which ended up resulting in the video escapades.