What is the actor doing when script says aside?

An "aside" in a script is a line or passage spoken by a character directly to the audience, unheard by the other characters in the scene. The actor delivering an aside typically turns away from the other actors and speaks to the audience directly, often breaking the fourth wall of the play. Asides are often used for comedic effect, to express the character's inner thoughts or feelings, or to provide exposition that the other characters are not privy to.