Guest stars

In show business, a guest appearance is the participation of an outsider performer (such as a musician or actor) in an event such as a music record or concert, show, etc., when the performer does not belong to the regular cast, band or other performing group. In music, such an outside performer is often referred to as a guest artist. In performance art, the terms guest role or guest star are also common, the latter term specifically indicating the guest appearance of a celebrity. The latter is often also credited as "special guest star" or "special musical guest star" by some production companies.

In pop music, guest appearances are often described with the words featuring, with, or and. It is abbreviated in credit lists as feat., ft., f/, f..

In a television series, a guest star is an actor who appears in one or a few episodes.

In radio and television shows, a guest star is a guest of the show who is a celebrity.

Guest appearances have been known in theatre, ballet, and classical music for centuries, with guests both from the home country and from abroad. The advent of air transport has made this practice much more practical and global.

In classical music, guest orchestra conductors are a common practice.

Guest artists should not be confused with touring groups, troupes, orchestra, or even individual artists, although the distinction may be blurred. In the case of touring, their act is independent in itself, while the guest takes part in the act of the resident staff.

The duration of involvement of a guest artist may vary, from separate short-term acts with fees per concert to fixed temporary contracts for several seasons.

...
Wikipedia