A Cameo appearance (often shortened to cameo), is a brief appearance by a celebrity in a film or TV show. 

 

A cameo is literally a relief carving of a head or bust on a piece of jewelry such as a cameo brooch. Originally cameos referred to appearances by celebrities in which they played themselves. Now the term can include brief appearances by actors playing a part other than themselves as well.

 

One of the most famous implementers of this technique was Alfred Hitchcock, who often inserted himself into his films as a bystander. 

 

Although Hitchcock was famous for his own cameos, many directors have followed in his tradition.

 

Director Martin Scorses appears as a gangster in Who’s That Knocking at My Door, a pedestrian in Taxi Driver, a wealthy New Yorker in Gangs of New York, and a theatergoer in The Aviator.

 

In The Sixth Sense, M. Night Shyamalan plays the small role of a doctor at the hospital while in Unbreakable, he appears as a shady fan Bruce Willis searches at a stadium. In Signs, he is the vet Ray Reddy, who is involved in the accident that took Graham's wife's life.

 

One of the funnier cameos occurs in Annie Hall (1977) when the main character, Alvy Singer (Woody Allen), is annoyed by a know-it-all in line at the movie theatre. The obnoxious moviegoer is spouting theories about Marshall Mcluhan and Allen brings out Marshall Mcluhan who dutifully says, “I've heard what you were saying. You know nothing of my work..." Alvy looks at the camera and says "boy, if life were only like this!"

 

Cameos are not limited to famous actors and directors, but can include athletes, politicians, musicians, and others.