Actors who played roles either in interactive movies or as voice actors in video games, at least once in their career. In general they are of use when they need to continue the story of the game with a video segments. Also they use them for voice over when you are controlling your character, and it encounters something.
According to the Internet Movie Database, in 1992 there was a game called Night Trap starring Dana Plato it was one of the first or the first time an established celebrity worked on a video game. In 1993, Corey Haim was in the video game Double Switch. Christopher Walken and Paul Giamatti were also in a 1996 Interactive Movie called the Ripper. Ever since actors and celebrities have done large amounts of work in video games.