A guest appearance — temporarily performing or appearing (on stage, in a show, etc.) as a guest artist or performer.
有名な俳優がその舞台に客演することになった。
A well-known actor will make a guest appearance in that play.
彼はコンサートに客演として招かれ、一曲だけ歌った。
He was invited as a guest to the concert and sang just one song.
テレビ番組の客演によって視聴率が上がった。
The guest appearance on the TV program raised the ratings.