 There are only five actors to play the same character on three  different "Star Trek" series: Jonathan Frakes (qv)  (Commander/Captain William T. Riker), Marina Sirtis (qv)  (Counsellor Deanna Troi), Armin Shimerman (qv) (Quark),  John de Lancie (qv) (Q), and Richard Poe (qv) (Gul Evek). They  all appeared in "Star Trek: The Next Generation" and "Star Trek:  Voyager."