William Mapother is an American actor who is best known to small-screen audiences for his portrayal of Ethan Rom in the television series Lost. Born in 1965, the Kentucky native is the first cousin of well-known actor Tom Cruise and has acted in five films with his more famous relative. Mapother has gained credibility in Hollywood for his portrayal of a number of dark or mysterious characters, with major features in Todd Field's In The Bedroom and Rom's character in Lost. In particular, Mapother gained a following in Lost largely due to the fact that his character was killed in the first season, but remained in the series through visions and flashbacks that amounted to appearances in 11 episodes. On the big screen, Mapother had a cameo with Cruise in Minority Report (2002) and Vanilla Sky (2001), and a supporting role in Mission Impossible: II (2000), Magnolia (1999) and Born on the Fourth of July (1989). Behind the scenes, the actor is also a member of the National Board of Directors for the Screen Actors Guild.