Glee

Several times during filming they had to stop rolling to tell Kevin McHale to stop tapping his feet to the beat of the music.

Heather Morris (who had been a back-up dancer for Beyoncé Knowles' tour) was hired to play the character of Brittany after she was first called in by show choreographer Zachary Woodlee to teach the "Single Ladies" dance to the cast.

On the day of her audition, Lea Michele was in a car accident right outside of the studio. She came in literally still pulling glass from her hair.