Sometimes, games are produced with the involvement of a celebrity without being based on any particular existing property, such as a movie or TV show that the celebrity appeared in. For example, Shaq Fu is a fighting game that prominently features the likeness of former NBA star Shaquille O'Neal. Shaq Fu exists primarily because O'Neal's name is attached.
This is different from games that merely feature celebrities, rather than directly relying on them to sell the game. Afro Samurai features the voice work of Samuel L. Jackson, but sells itself on being an action game starring a character that happens to be voiced by Jackson. Similarly, although it stars the latest actor to play James Bond, 007: Blood Stone is a game about James Bond, not about Daniel Craig. This also applies to games in which celebrities are given star billing for character portrayals. For example, two characters in Beyond: Two Souls are voiced by and modeled after Ellen Page and Willem Dafoe, whose names appear on the game's cover, but the actors themselves do not dominate the game's image.