10 Actors Who Appeared In Star Trek AND Battlestar Galactica

8. Rick Worthy

Rick Worthy has played more roles in Star Trek than anyone else on this list. Close as close can be to a Cylon — if we're talking 'chrome job toaster' Cylon — Worthy first appeared as Automated Unit 3947, and Automated Commander 122, in the Star Trek: Voyager episode Prototype.

From there, Worthy would portray Klingon Kornan in Star Trek: Deep Space Nine's Soldiers of the Empire, an Elloran officer on Ru'afo's ship in Star Trek: Insurrection, and Jannar, Xindi council member, in several episodes of Star Trek: Enterprise. In that time, he would also return to Voyager as the less-than-likeable Noah Lessing in Equinox, Parts I & II.

Worthy's first appearance in Battlestar Galactica was in the second season's bone-chilling episode The Farm, though the actor was already an avid fan of the show. Worthy's character, Doctor Simon, is quickly revealed to be a humanoid Cylon — one of the Number Fours. Quite the upgrade from his Automated Unit days!

Worthy returned as Number Four, also called Simon O'Neill in one of his guises, in a further eight episodes across the remaining seasons, as well as the 2009 TV movie The Plan. If a lot of the Simons were medics, as in The Farm, it was best, as a rule, not to ask for a second opinion from a Number Four.