(right) on cue

What is the origin of the idiom "on cue" and when to use it?

The idiom "on cue" originated in the theater and performance industry, specifically in the context of stage acting. It refers to the precise timing and execution of an action or line of dialogue in response to a cue, which is a signal or prompt given by another performer or stage manager. Today, it is used in various contexts and occasions where precise timing or coordination is important.