Sorry, Taylor Swift. It looks like you aren't the only solo superstar who can surprise your audience with some very special guests.
During a concert this week in Chicago, Billy Joel broke into a rendition of "Uptown Girl," a beloved classic that is featured in the comedy Trainwreck.
And that comedy was written by Amy Schumer, who is new best friends with Jennifer Lawrence... and who shocked attendees by jumping on stage and dancing with the actress on top of Joel's piano.
We're not making this up, nor are we exaggerating when we say this may be the single greatest piece of footage ever recorded in human history.