Simon Rex (born July 20, 1974, in San Francisco, California is an American actor and model. Rex began his career by masturbating in a series of pornographic films oriented towards gay men. (The films are entitled Hot Sessions 3 and Young, Hard & Solo #3. He is billed as "Sebastian," and they sell for upwards of $1,000 on eBay.) He was hired as an MTV VJ but was consequently fired when his pornographic past was revealed.

He began to pursue legitimate acting and was cast in a pilot television show called Jack & Jill in 1999. The show was critically panned and cancelled quickly. He had a brief stint as "Eli" in the T.V. show Felicity. A string of television guest appearances followed (including Baywatch), as well as cameos in various films. In 2002 the pilot for the show What I Like About You was picked up, but once again his work was critically panned. The series was cancelled.

Rex most recently appeared in the film "Scary Movie 3".