A cameo appearance, also called a cameo role and often shortened to just cameo, is a brief guest appearance of a well-known person or character in a work of the performing arts. These roles are generally small, many of them non-speaking ones, and are commonly either appearances in a work in which they hold some special significance or renowned people making uncredited appearances. Short appearances by celebrities, film directors, politicians, athletes or musicians are common. A crew member of the movie or show playing a minor role can be referred to as a cameo role as well, such as director Alfred Hitchcock who made frequent cameo appearances in his films.

Cameo is a method of carving an object such as an engraved gem, item of jewellery or vessel. It nearly always features a raised (positive) relief image; contrast with intaglio, which has a negative image. Originally, and still in discussing historical work, cameo only referred to works where the relief image was of a contrasting colour to the background; this was achieved by carefully carving a piece of material with a flat plane where two contrasting colours met, removing all the first colour except for the image to leave a contrasting background.