This really had me confused so I checked AllMovie Guide. Catrall was in a Star Treck film, but it was hardly an early one. It was number six, The Undiscovered Country.
So, I suspect that the person you were thinking of appeared in ly someone who back then was quite nice, IMO but is now. to borrow a phrase from SNL, "A rapacious swamp sow":
Kirstie Alley in Star Trek II, with her Vulcan Ears:
And looking mighty fine without them, back in the day"
(sorry for turning this into the Babe thread. Maybe I could post a picture of Kirstie now, to make you forget what she looked like then?