Martin's father was a singer, and his mother was an actor and extra. In 1975, he had acted in a few adverts by the end of school, but needed to get a proper job. He got a cabaret act together and started performing on a cruise ship at 17. In 1976, he made his debut in the West End theatre with Jesus Christ Superstar at 18 after a period of training at the London Academy of Music and Dramatic Art.