Old Mother Riley in Society (1940)

Old Mother Riley does the laundry for the dancers in the pantomime "Aladdin", where her daughter Kitty works as a chorus girl. Sneaking a peek at the show one day, Mother Riley accidentally pops up through a trap door onto the stage. Accosted by the angry star, Mother Riley’s belligerent responses have the audience in stitches. Outraged, the star walks out, leaving Kitty to take over the leading role, to great success.