(written from a Production point of view)
David "Dave" Somerville (2 October 1933 – 14 July 2015; age 81) was a Canadian singer who played Lieutenant Larry Matson in the Star Trek: The Original Series first season episode "The Conscience of the King". He was credited as David-Troy. He filmed his scene on Friday 16 September 1966 and Monday 19 September 1966 on Desilu Stage 9.
Somerville was best known for the eight years he spent as the lead singer of the popular 1950s quartet The Diamonds, a group whose hits include 1957's "Little Darlin" and 1958's "The Stroll". He left the group in 1961 and embarked on a solo career under the name "David Troy". He later joined another popular quartet, The Four Preps, and even formed his own groups, WW Fancy and Somerville's Diamonds. Over the years, he continued to associate with The Diamonds and The Four Preps.
Somerville studied acting with Leonard Nimoy. Besides Star Trek, he has also appeared on the television shows McCloud (with Whit Bissell and Ken Lynch), The Amazing Spider-Man (with Ellen Bry), and Quincy, M.E. (starring Robert Ito and Garry Walberg). He also co-wrote the theme song for the hit ABC series, The Fall Guy.
In the years before his death, Somerville had been singing with a group called Triple Gold, a trio of singers who represented the groups The Diamonds, The Four Preps, and The Association. He also continued to perform as lead singer of The Diamonds for concert shows. He performed under the name "Diamond Dave" Somerville.