"Captain" Kirk Douglas (born September 30, 1973) is an American guitarist and singer who performs with the hip hop band The Roots. He joined The Roots in 2003. His first album with The Roots was 2004's The Tipping Point, where he split guitar duties with Martin Luther and Anthony Tidd. By the release of their 2006 album Game Theory, he had assumed the role as sole guitarist for the band. As a vocalist, he serves as the band's primary melodic singer, sharing duties with American rapper Black Thought.