A headliner is the main act in a music, theatre, or comedy performance. Generally, the headliner is the final act in a performance, preceded by the opening act(s).

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In music, the headliner often reserves sole permissions to the name of the tour. Thus, tour names often reflect the name of the latest album or a popular song from the latest album of the headliner. Additionally, the headliner is often the most famous or prominent act in the performance.

The main event is a similar concept in sports.