Watch: Jennifer Lawrence & Amy Schumer Dance On Billy Joel's Piano

Just the other day, Jennifer Lawrence let slip that she and new best friend Amy Schumer are writing a film together--and that they'll be playing sisters! The two really are inseperable, it would seem, as they made a surpise appearance at a Billy Joel concert in Chicago last night. When Joel began performing 'Uptown Girl,' Schumer and Lawrence hopped on-stage (and on-piano) and got to dancing.

Schumer tweeted her own verison of the performance: