William Shatner made history with US TV's 1st interracial kiss

As Nichols recounted in an interview, she thought about quitting "Star Trek" after its first season when she was offered a gig in a Broadway-bound play. She went as far as to hand creator Gene Roddenberry her resignation letter.

Roddenberry pleaded with Nichols to stay, urging her to think deeper about the decision.

As fate would have it, she soon ran into a fan at an event. That fan was none other than Dr. Martin Luther King Jr.

Dr. King told Nichols she couldn't leave the show, explaining how crucial her role was in how women and Black people were seen.

"For the first time on television, we will be seen as we should be seen everyday, as intelligent, quality, beautiful people...who can go into space, who can be lawyers, who can be teachers, who can be professors," she recalled him saying.

"Gene Roddenberry has opened a door for the world to see us. If you leave, that door can be closed," Nichols added.