(written from a Production point of view)
Barbara Ann Luna (born 2 March 1939; age 74) is the actress who played Lieutenant Marlena Moreau, as well as her mirror universe counterpart, in the Star Trek: The Original Series episode "Mirror, Mirror".
Luna was once a regular on the the daytime soap opera One Life to Live playing leading man Cord Roberts' scheming mother Maria from 1986 through 1987. She has also appeared in several episodes of Buck Rogers in the 25th Century, Mission: Impossible (which, like the original Trek series, was produced by Desilu) and Fantasy Island (starring Ricardo Montalban). She also appeared in at least one episode of T.J. Hooker, a series which starred TOS actor William Shatner.
In 2004, Luna portrayed Veronica in the Star Trek: New Voyages (now Star Trek: Phase II) episode "In Harm's Way" and appeared alongside fellow Trek performers William Windom, James Cawley, Jeffery Quinn, Malachi Throne, John Carrigan, Sam Witwer, and Leslie Hoffman. The story for this episode was written by Doug Drexler. In 2008, she portrayed Alersa in the Star Trek: Phase II episode "Enemy Starfleet".