From ST3:TSFS -- in the freighter that meets up with Kruge's ship to deliver the Genesis data, there's an alien crewmember on board (entirely separate from Valkris.)
Yes! Now, this is very strange, because for all the time and money that went into this "alien," there's just this quick, distant reaction shot of the back of his head, just as Kruge's blowing the ship up. It's hard to believe that it looked like shit and that's why, when it had to be tested and approved, every step of the way. An odd directorial decision, to say the least. Perhaps Nimoy felt that the impression of Valkris being the only alien onboard, added to her regal, even exotic, appearance?