Celebrity cameo roles are nothing new to the entertainment industry. Big name stars, athletes and artists have slid into the background of hundreds of films, oftentimes acting as a comedic addition to the scene or an homage. Ever see an Alfred Hitchcock film?
But the best type of cameo -- one that has taken off recently -- is the on-screen appearance of a celebrity who is acting as him or herself. Though some cameos are more refined, most self-parodies tend to be a bit exaggerated for your viewing pleasure -- Topher Grace in "Ocean's Twelve," for example.
Which begs the question, if these stars are parodying themselves, are they really acting?
Some still are, just ask Elizabeth Moss about her ex-husband Fred Armisen.
Check out the gallery below to see some of the best celebrity cameo self-parodies. And if you really want to challenge yourself, try to guess the movie or TV show the celeb appeared in (answers at bottom of photo).