The Twilight Zone and Star Trek are cornerstones of classic TV, entertaining generations of viewers and still influencing popular culture. However, even die-hard fans of both shows may not realize that four original cast members of Star Trek took a pit stop at Rod Serling’s fantasy series before Gene Roddenberry’s space saga even began production.

William Shatner starred in two iconic episodes of ‘The Twilight Zone’

Of course, Captain Kirk himself, William Shatner, made two famous starring appearances on The Twilight Zone. Shatner’s second guest spot on the series is perhaps his most iconic and often referenced. Season five’s “Nightmare at 30,000 Feet” finds the future Starfleet captain tormented by a furry gremlin hanging out on the wing of an airplane he’s flying in.

The episode, penned by prolific writer Richard Matheson (I Am Legend), is so memorable that it was remade as a segment in The Twilight Zone: The Movie. However, Shatner made an earlier appearance on a fan favorite of the legendary series. In season two’s “Nick of Time”, he plays a man obsessed with a small fortune-telling machine in a diner. The little devil-headed device has become a symbol of the series.

Leonard Nimoy

That’s right, the legendary Mr. Spock, Leonard Nimoy, also made a stop over at The Twilight Zone. “A Quality of Mercy” is a season three episode of the series, and Nimoy has a small part in the proceedings. Nimoy portrayed Hansen, an American soldier, while Dean Stockwell played the lead, an officer who led a charge on Japanese soldiers during WWII.

Of course, supernatural shenanigans are afoot, and Stockwell’s character trades places with a Japanese officer, allowing him to earn true empathy for his enemy. Again, the future Vulcan’s part is small, but Nimoy still manages to stick out with his trademark charm and deep voice.

George Takei starred in a controversial episode of ‘The Twilight Zone’

Sulu himself, George Takei appeared in an episode tackling racial prejudice. In “The Encounter” from season five, Takei plays Arthur Takamori, a man in search of work who visits the home of Fenton, a World War II veteran. A samurai sword that Fenton took home from the war seems to possess both men, leading to a tense showdown in an attic. The acting between Takei and his co-lead, Neville Brand is electric and tense. Though the lesson about racial intolerance may seem heavy-handed by today’s standards, it likely packed quite a punch in the 1960s.

James Doohan

Chief Engineer Montgomery “Scotty” Scott appeared in season four’s “Valley of the Shadow.” James Doohan manages to cut his sci-fi chops in this episode, which unfolds as a journalist finds themselves ensnared within the enigmatic confines of a secluded town, concealed from the world, brimming with extraterrestrial advancements beyond imagination.

Like Leonard Nimoy’s appearance in The Twilight Zone, Doohan’s role is fleeting. He plays an inhabitant of the town (and without his iconic Scottish accent he put on for Star Trek). Though over-stuffed as an hour-long episode, the twist and moral dilemma still are effective.