Mark Lenard

Had to have his hair dyed and makeup applied to his face to make him look older while playing Sarek, the Vulcan father of Spock on "Star Trek" (1966) because in reality he wasn't that much older than Leonard Nimoy, who played Spock.

In addition to having played all three (at the time) major aliens in the Star Trek universe (the Romulan commander in the original series "Balance of Terror", the Vulcan Sarek, and the Klingon captain in Star Trek: The Motion Picture (1979)), he also almost played a human - Gene Roddenberry wanted him to portray Abraham Lincoln in "The Savage Curtain" (the episode where Kirk, Spock, Lincoln, and Vulcan legend Surak represent "good" in a staged battle with Genghis Khan and three others representing "evil"), but Lenard was unavailable at the time.