Roy Thinnes (born April 6, 1938) is an American television and film actor best known for his portrayal of lonely hero David Vincent in the ABC 1967–68 television series The Invaders.
He also played Alfred Wentworth in the pilot episode of Law & Order. He starred in the 1969 British science fiction film, Journey to the Far Side of the Sun (also known as Doppelgänger).
Thinnes was born in Chicago and educated at Los Angeles City College. His ethnic background is German. His first primetime role was as a brother of ex-cop Lee Marvin in a 1962 episode of The Untouchables, called "A Fist of Five". Later he appeared as Ben Quick in the short-lived 1965-66 television series The Long Hot Summer, which ran on ABC. During its run he received around 1,500 letters a week from women and appeared on the cover of TV Guide (April 9–15, 1966 issue) for his one and only time to date. The TV series The Invaders soon followed, with Thinnes playing an architect named David Vincent who accidentally witnesses the arrival of aliens from another planet and wages a seemingly hopeless one-man campaign against them. The series became a cult classic, leading to other 'aliens vs earthlings' films and TV shows.