Martel died Tuesday from complications of a heart attack at St. John's Health Center in Santa Monica, her son, Jod Kaftan, told The Hollywood Reporter.
In the episode "Amok Time," which opened Star Trek's second season on Sept. 15, 1967, a feverish Spock is compelled to return to his home planet, where he must "mate or die." Martel's character, T'Pring, was betrothed to him as a child, and the outcome of a fight between Spock and Captain Kirk (William Shatner) will decide whether she marries the logical first officer on the Starship Enterprise.
"I was just so happy to be working and playing a part that was so challenging in terms of what I had done before," Martel said in Tom Lisanti's 2003 book, Drive-in Dream Girls: A Galaxy of B-Movie Starlets of the Sixties. "I had no idea it would continue to this day. Fans purchase my Star Trek photos at conventions, where I sign autographs. I had no idea that T'Pring would be so memorable to people."
Said Nimoy on Twitter: "Saying goodbye to T'Pring, Arlene Martel. A lovely talent."
In the 1957 Warner Bros. documentary The James Dean Story, directed by Robert Altman, Martel said she was romantically involved with the actor for years. "Once I told him I loved him, but he pretended he didn't hear," she says in the film. "Then he said, 'You can't love me. I don't think anyone can yet.' "
Memorial services are pending. The family asks that donations be made to the organization Autism Speaks.