The theme around here of late has been all about the actors behind our favorite characters–or sometimes the smaller characters, who are important nonetheless. When it comes to casting in a shared universe, sometimes it turns out the best man or woman for the job might look a little… familiar. You go back and look, and yep, they’ve already had a part somewhere in there! Sometimes this results in a reworking of the plot, changing the new character to be the same as the old, like Stargate Atlantis did with David Hewlett’s Rodney McKay. Other times, there’s a little joke where the resemblance is brought up, or the problem is ignored altogether. So here are 4 cases where the actor or actress previously showed up in a small part before breaking through to the main cast, and how the show dealt with it.

4. Freema Agyeman–Doctor Who

They could’ve reused her, except for the whole being dead thing.

Freema Agyeman is better known to most Who fans as Martha Jones, companion to the 10th Doctor throughout series 3 (and a frequently returning one at that). But before she was cast as Martha, she had another role–in the first half of the two-part finale for series 2, as an employee for Torchwood. Which means that, weirdly enough, there’s precisely two episodes between her small part and her start as a companion. That’s way too close to ignore the connection, and on rewatches, it’s very obviously her; the part is actually fairly prominent, as… spoiler alert, her character is one of the first to be converted to a Cyberman. The way they decided to deal with this was to throw an offhand comment about her “cousin” who died at Canary Wharf during the big Cyberman/Dalek showdown. Her completely identical cousin! I wonder if Martha’s family ever got nervous when she eventually started working with Torchwood, too…

Doctor Who engages in this quite a lot, probably to no one’s surprise; from new Who alone, Karen Gillan (Amy), Peter Capaldi (the current Doctor), and Eve Myles (Gwen from Torchwood) all appeared in guest roles before taking on their better known starring roles. Gillan was under makeup and only briefly seen, so she got a pass; Capaldi’s two previous roles (one of which is in the same episode as Gillan’s!) are supposedly going to be explained on screen next series; and Myles’ was mentioned in-universe in the big crossover episode “Journey’s End,” where the Doctor noted it as a case of “spatial genetic multiplicity,” whatever that means.

3. Robert Duncan McNeill–Star Trek (VOY and TNG)

He even kept the same hair style!

This one’s pretty well known, and has been a source of endless debate. See, McNeill originally played Nick Locarno from the TNG episode “The First Duty.” And in that episode, Locarno is responsible for a coverup when his top-notch cadet squadron tries a risky piloting maneuver that ends up killing one of them. Locarno was kicked out of Starfleet Academy as a result, and never seen again. Later, McNeill played Tom Paris, a Starfleet officer who was responsible for a coverup when he made a piloting error. Sound familiar? Yes, his two characters ended up with very similar histories. The main difference is that Paris graduated before screwing up and Locarno didn’t.

The explanations for why they didn’t reuse Locarno has varied over the years, and it’s not clear to this day. Some say that it was a money issue, and that they’d have to pay royalties to the writer of “The First Duty” every time Locarno appeared on screen. Others say the difference is in how the characters handled the incident: Locarno tried to cover it up, and forced Wesley and other cadets to participate in his deception. It was only when Picard and Wesley forced his hand that he came clean and sacrificed his career in an attempt to save that of Wesley and the others. Paris, on the other hand, involved no one else in his coverup and came clean of his own accord, out of a guilty conscience. This difference is what is said to make Paris’s character redeemable, and Locarno’s irredeemable. Which to believe? Depends how cynical you are, I guess.

2. Paul McGillion–Stargate (Atlantis and SG-1)

You might not recognize him, what with the 1940s American accent and it being 10 years before SGA.

Paul McGillion played the Scottish doctor (but not the Scottish Doctor) Carson Beckett on Stargate Atlantis. And while he had some leaving-and-returning to the cast action on that show, it’s not why he made the list. Because you see, McGillion had another, very small spot on the parent show, SG-1, way back in its first season. And while Stargate is usually great about bringing back actors as the same character (as mentioned above), there’s a good reason why they didn’t.

McGillion’s first role in Stargate was in a flashback in the first season episode “The Torment of Tantalus,” as a man from 1945, Ernest Littlefield, who managed to dial the gate by surprise and never made it back. While an older version of Littlefield is eventually encountered and recovered by SG-1, that version wasn’t played by McGillion (…obviously). Since it was such a small part, and the whole ordeal was just one of those first season episodes that didn’t hold much significance, there was never a need to address it.

1. Steve Bacic–Andromeda

Genetic reincarnation is just a really, really handy thing to have around from a casting perspective.

In the first episode of Andromeda, we see some of Dylan’s original crew before he’s frozen in time at the edge of a black hole. One of these characters from the original crew is Gaheris Rhade, played by Steve Bacic. He seems to betray Dylan for no reason, but through flashbacks and a whole spotlight episode, we get to see what led to his betrayal: a recognition that Dylan had to be the one sent forward, because only he could restart the Commonwealth and save the three galaxies. This made him a pretty popular character, but, you know, he was dead and from 300 years in the past.

Then later on in the show, when t hey needed some new cast members, someone decided to call Steve Bacic up again. Cause you see, Gaheris Rhade was a Nietzschean, and one of the unusual aspects of their race is that low genetic diversity means “genetic reincarnation”–that is, a descendant can be born with genes so close to his that the kid is effectively a clone. Thus appeared Telemachus Rhade, the genetic reincarnation of Gaheris. On the scale of explanations for recasting an actor, this is a pretty solid explanation; it’s a pre-established trait of the species to which the original character belonged, one that was critical to their philosophy and existence. The actual plausibility behind it is pretty much irrelevant, because of how ingrained it is in the series.

Are there any other cases of small-part actors eventually returning as main cast members that you know about? Let me know in the comments, or on Twitter @RetroPhaseShift. Monday’s What Could Have Been is going to be delayed a few days, mostly because of the Primer taking longer than usual and the last Monday being as early as possible in the month this time around. Unlucky coincidence for me, I guess.