Star Trek Phase II: 3 characters who were going to be main cast members

Xon

Each character on this list has its own distinction. Will Decker appeared in Star Trek: The Motion Picture but was never cast. Ilia was cast for the show and ended up in the film. Xon, on the other hand, was cast for Phase II but was never brought to the big screen. Not just for Star Trek: The Motion Picture, but for any Star Trek film.

Thankfully for the man who played Xon in the Phase II series, David Gautreaux was not forced to suffer the same fate. He appeared in the film, albeit in a minor role as Commander Branch. A role he may not even have gotten if Majel Barrett had gotten her way. He got the role in the film because they opted not to use his original character, Xon.

Apparently, Barrett thought Gautreaux was playing a love interest for her and was too young. There was some confusion on her part about who Gautreaux would play, and fearing that her unrequited love angle with Spock wouldn’t play with the younger actor, demanded that they cast an older actor.

He got to keep the gig and apparently even became the first member of Phase II to find out about the series transitioning into a film. A film his character would ironically never see.

The character was meant to be a lot like what T’Pol would be in Star Trek: Enterprise. A full-blooded Vulcan who looked down on humans. Some of his mannerisms, like his inability to grasp the culture of Earth-born humans, would apparently transition into the character of Data.