(Wilson Cruz and Anthony Rapp. Screenshot via CBS News.)

Wilson Cruz and Anthony Rapp will portray the first gay couple onboard ship in the “Star Trek” franchise on ‘Star Trek: Discovery.”

Cruz will play medical officer Dr. Hugh Culber and Rapp will be starfleet officer Lt. Paul Stamets. The stars told CBS News that their relationship will be full of firsts for the series.

“This is the first time two human beings who are in love with each other as the same gender. It’s the first of that [on Star Trek]. Even the fact that he’s Latino and I’m white,” Rapp says. “These are just factors and then you get to know us as human beings on the ship as all the other human beings on the ship are. We are also colleagues. He’s a medical officer, I’m a science officer, and our work intersects sometimes. All that stuff is just part of the fabric of it.”

A gay relationship will be monumental for the show, but Rapp says it won’t be the only focus.

“The storyline affects our relationship, and the relationship may affect some decisions that are made, but the fact that it’s two men in a relationship is not the focal point of any storyline,” Rapp says.

Cruz added that navigating work with an onboard relationship will prove challenging for the couple.

“It enrichens the storyline,” Cruz says. “The crux of my journey is how I balance my responsibilities as the ship’s doctor with my responsibilities to the person I love, and how those two ideas can come into conflict at times.”

“Star Trek: Discovery” premieres on Sunday, Sept. 24 at 8:30 p.m. on CBS. The rest of the season will stream on CBS All Access.