(written from a Production point of view)
Jerry Zimmer (died May 1 2005) was the pianist who performed the piano play of Amarie in the Star Trek: The Next Generation episode "Unification II". His arms were also seen as the second pair of Amarie's arms in this episode and he was present during the regular shootings with Harriet Leider on 17 September 1991 and 18 September 1991 and the second unit inserts on 29 October 1991. During the second unit shots the second pair of arms beside Zimmer's were portrayed by Leider's photo double Cindy White. The call sheets for his first days of shooting are listing him as "1 Musician (Zimmer)".
Zimmer was born in Cleveland, Ohio and studied with jazz pianist Bill Gidney.  Beside Star Trek, Zimmer also appeared as pianist in the television series Dynasty and Love Boat and worked as composer on the 1997 short film The Blue Hotel.