Opening act

The opening act's performance serves to "warm up" the audience, making it appropriately excited and enthusiastic for the headliner.

In rock music, the opening act will usually be an up-and-coming group with a smaller following than the headliner.

[3] They usually work alone and perform a comedy routine while also possibly explaining aspects of the show.

[1] Some warm-up routines before talk shows involve giving prizes to audience members.

[3] The use of warm-ups in comedy dates back before television to radio shows.