Billy Joel had a couple of very popular–and very sexy–ladies join him on stage during his concert in Chicago on Thursday night. The ladies were none other than new BFFs Jennifer Lawrence and Amy Schumer.

The pair danced barefoot atop a piano while Billy Joel sang his long-popular “Uptown Girl.” The song was featured in Amy Schumer’s film Trainwreck.

Many fans believed the two showing up on stage was a complete surprise to Billy Joel, but in truth they’d rehearsed all day alongside the Piano Man at Wrigley Field.

“Billy came out for his encore and started singing “Uptown Girl,” ” an audience member told People magazine. “And then Amy and [Jennifer] came out with some others for the song! Eventually Amy and [Jennifer] were dancing on Billy’s piano. Absolutely loved it.”

Watch Jennifer Lawrence and Amy Schumer Dance Barefoot on Billy Joel's Piano http://t.co/NY7ktg0cVN pic.twitter.com/72jhT6SAUW

— Hollywood Reporter (@THR) August 29, 2015

Amy Schumer shared a photo to her Instagram account of herself with Jennifer Lawrence, standing on Billy Joel’s piano.

“Piano men,” she captioned it.

A photo posted by @amyschumer on Aug 28, 2015 at 6:29am PDT

She also posted footage of the piano scene, with Billy Joel singing on stage.

A video posted by @amyschumer on Aug 28, 2015 at 6:10am PDT

Amy Schumer and Jennifer Lawrence have been vacationing together. Wouldn’t it be a blast to get invited along?

The two recently announced they are writing a screenplay together, too.

Maybe they’ll ask Billy Joel to write the theme song.