William  Shatner became a cultural icon for his portrayal of James T. Kirk, captain of  
the Star Ship Enterprise, in the Sci-Fi television series Star Trek from 1966 to 1969,
Star Trek: The Animated Series from 1973 to 1974, and in seven of the subsequent
star Trek feature films from 1979 to 1994. Shatner also played the veteran police sergeant in T.J. Hooker from 1982 to 1986. He has since worked as a musician,
author, producer, director, and celebrity pitchman. He has won two Emmy Awards
and a Golden Globe Award.

William Shatner in The Twilight Zone episode “Nightmare at 20,000 Feet”(1963)

Dean Stockwell is an actor of film and television, active for over 60 years 
and unlike many child actors, he continued to act well past his teenage
years. He is most known for his role as Rear Admiral Albert “Al” Calavicci
in the NBC television series Quantum Leap (1989 – 1993) and in the Sci 
Fi revival of Battlestar Glactica as Brother Cavil.

Young Dean Stockwell in Anchors Aweigh (1945)

Dean Stock as a Japanese soldier in  A Quality of Mercy a Twilight Zone
episode in 1961.

Dean Stockwell with costar Scott Bakula, right, in Quantum Leap