Real World article
(written from a Production point of view)

John Watts is a Star Trek fan who appeared as an Andorian Enterprise crewmember in the recreation deck scenes in Star Trek: The Motion Picture. Watts appeared as an Andorian on Star Trek conventions for three years, before he got coincidentally cast as one in the film. On the set, he asked Bjo Trimble, "How did they know?" (Starlog #56, March 1982, p. 27; [1])