Cynthia Erivo is a proponent of fans being able to sing along to songs from her musical "Wicked" at the movies, despite what theaters say.

There’s no need to flex those vocal cords ahead of going to the movie theater this week. Break out your best pink ensemble. Paint yourself green. But resist the urge to make watching the film adaptation of the Broadway musical a sing-a-long — at least at AMC Theatres.