On Orphan Black, BBC’s exquisite mind-meld of a sci-fi series, actress Tatiana Maslany delivers the best performance on television. Because she pulls off about a dozen of them.

The drama, which returns Saturday night for its third season, is such a gloriously complicated spider web—or, more accurately, DNA double helix—that it’s nearly impossible to explain succinctly. At its simplest, it chronicles the fight for survival, on their own terms, by a group of women who, when they’re grown, discover that they are actually clones. Maslany plays all of these women: a streetwise British hustler, an uptight soccer mom, a bisexual biologist, a Ukranian assassin…and so many more.

It is hard to imagine a single actor on television with a more challenging role (rather, roles) than Maslany. Well, meet Ari Millen.

In the shocking Season 2 finale, it was revealed that Millen would be playing an entire set of hitherto unknown male clones. But there’s a catch. All (well, most) of the genetically identical women played by Maslany grew up unaware that they were clones, and thus developed distinct personalities, accents, hairstyles, and even ethnic identities. The male clones, however, grew up as part of the mysterious military Project Castro, completely aware that they were identical, and, more, trained to be so.

So Millen wasn’t granted the luxury of wigs and accents in creating separate identities of his clones. (Thus far, we’ve met the kind-hearted but lethal Mark Rollins and the rabid and dangerous Rudy, aka “Scarface.”) Instead, he’s been tasked with crafting discernible and unique clone characters while maintaining the same look, hairstyle, and military backstory for each character.

It's no easy task—not that Millen is complaining.

He was first introduced as Mark Rollins, a member of the cult-like Proletheans with nefarious ties to the female clones. Mark actually was supposed to, in the original plans of creators John Fawcett and Graeme Manson, be killed off by Episode 6 of the second season.

No one was more surprised than Millen, then, when he received a phone call from Manson alerting him that, not only is Mark going to stick around, but he will be a linchpin member of a newly introduced breed of male clones—and, like Maslany before him, Millen would play them all.

That’s how, in a short whirlwind, Millen has found himself at the center of one of the most exciting storylines for fans of a show that viewers support at an obsessive level. (They call themselves “Clone Club.”) He also found himself creating his new characters with undue short notice, navigating the biggest acting challenge of his life, and, in one spectacular scene from Saturday’s premiere you’ll want to be ready to rewind, doing pull-ups naked in front of the entire world.

Meet the singular Ari Millen, the man behind the many men of Orphan Black.

That finale from last season with the big reveal. How do you keep something like that a secret? Did you have to keep it from everyone, even your family and friends?

(Laughs) I only told my girlfriend and my agent when I found out. I kept it a secret from everyone else. I was really hoping for the payoff when I watched it with my friends, to turn and see their reactions. And I got that. It was well worth the wait

So you watched the big reveal with your friends?

Yeah. We’d been watching the season together. We made plans to have a little get together for the finale. It was great.

You have to tell me more about the scene in the room when your friends find out that you're going to be playing a new set of clones.

(Laughs) Let’s see. Cassandra, my fiancée, started crying. Out of happiness! My one friend’s jaw dropped, another friend just looked at me, and my other friend just started laughing uncontrollably. Ha!

That’s a good payoff, sure. But it had to have been a little bit of torture to keep something like this a secret.

No, I enjoyed it. I enjoyed it. Because I knew it was coming. It was this fun little thing that kept me motivated. It was a really exciting thing. I was just waiting for the payoff, and I got it.

What about the reaction from fans of the show? I’m sure immediately you were inundated on Twitter and social media.

Yeah. That was a pretty surreal thing, because I was pretty new to Twitter at the time. My agent told me I should get it because of the show, so I listened. And certainly it was fun to see all the comments from the cliffhanger at the end of the season.

And you’re all of a sudden a major part of the Clone Club. I’m sure you spent months fielding questions and comments from everyone obsessed with the show and wanting to know more.

I mean just going to Comic-Con alone, that’s an unreal experience on its own. I think if everyone in the world could experience that place it would change their outlook. It’s just one big lovefest. It’s pretty incredible. But yeah, it was kind of being thrust into the spotlight. I don’t know if I’ll ever get used to it, but it’s something that thankfully gets easier as it goes. But wow.

There are few fan groups that are more passionate, loyal, or obsessive than Clone Club.

Clone Club is unreal. More this season than ever, I think, writers recognized the sort of diehard craving. Almost the detective work that they do, as far as when BBC was doing some teasers for the season they’d throw up some binary for a split-second and within hours of those new teasers being released the fans had already translated the binary. Pictures would get released from set and they would cross-reference them with other pictures they’d seen and try to suss out plot points and predict what’s going to happen in the season. And it’s pretty shocking how accurate some of those predictions can be. I think they know the show the better than even [show creators] John [Fawcett] and Graeme [Manson].

It’s been written a lot about how the original plan was to have Marc killed off. At what point did you get clued in to the fact that not only are you not getting killed off, but you’re going to be playing all of these other characters and have an even more pivotal role?

If I told you that it was day-of, it wouldn’t be that far off. I think we had already started filming Episode 209 when Grame called me and let me know. And I basically had just under two weeks to practice my pull-ups, as I like to joke.

How do you even react to news like that?

I think I’m still processing it. Excitement, elation. I think we probably opened a bottle of wine. Look, it’s the most exciting thing that’s ever happened to me in my career. Getting on the show was already the most exciting thing to happen to me in my career, and then to have this revelation that it was only going to get bigger—I’m really just so thankful. And it we really had a blast shooting this past third season. So I’m really excited to see it, because for the most part, the show is so complex and the schedule is so busy that I’ve, for the most part, forgotten most of it and am excited to see it for the first time coming up.

Did they give you a sense of why they chose you, or what about watching you play Marc put it in their heads that you would be the guy to play these clones?

I’m sure they had their reasons. I think that’s more of a question for John and Graeme, as to the specifics. But I know that Project Castor was always part of the plan. They just didn’t know who was going to be them. Thankfully, they picked me. I think from a storytelling point of view, the way that the third season goes with Marc and how that leads into Project Castor, there’s some pretty cool twists and turns that, for me, watching from the outside I would be really floored by. So I think they made the right decision in the storytelling sense.

You had the luxury of watching Tatiana play multiple roles before you were tasked with it, so I’m sure you had a little sense of what would be involved. But was there a challenge from it that you weren’t expecting?

For the most part, the biggest challenge I initially was anticipating was the multiple clone scenes, the technical side of it, which would be a new process for me. I was anticipating that being the challenge of the season, like acting to tennis balls and remembering my blocking. But that turned out to be not as difficult as I was expecting.

So what was the harder part?

Project Castor was raised together. They grew up together self-aware. Whereas Project LIDA only in their later life discovered they existed. So they developed completely as individuals, whereas Castor sort of grew up as a unit. So the challenge for me was finding the little bits and pieces of their individual personality in these larger similarities that the military would drill into them. So just finding those little aspects of what makes Rudy Rudy, what makes Marc Marc. And then on multiple clone day, shaking one mannerism off and bringing the other subtle mannerism in.

That’s a hard challenge. Not that Tatiana has it easy at all, but she has wigs and accents and different ethnicities to play with. You’re playing more nuanced shades.

Exactly. That was certainly the biggest challenge for me. But I did learn a lot of lessons just from sitting behind the camera and watching the monitor and seeing her maneuver her clone scenes and watching her work. Any of these amazing actors, really. Watching James Frain this season was incredible. Watching Maria [Doyle Kennedy] work. Watching Jordan [Gavaris] work. Speaking of transformations, Jordan to Felix is such a drastic change. It's so interesting to see him make those changes.

Tatiana has talked a lot about how important her body double has been in order to pull off this show and her performance. Your body double is actually a school friend of yours, right?

I was very lucky in that sense that there was no breaking of the ice needed. Nick Abraham and I had known each other from Ryerson University. So in pre-production we were working together and getting a sense—in pre-production, we were just learning who these guys were. So we were in essence developing these characters together, which is nice.

You seem like a friendly and down-to-earth person. How did you land on Rudy’s characterization? He’s so goddamned unsettling.

I guess, to a certain extent, he’s the opposite of who I am as a person. I’m more introverted and more reserved. So I guess it was exciting and also the challenge for me was pouring out that personality that doesn’t come naturally for me. That was the fun of Rudy, pushing my limits.

Are you prepared for the scene of you doing pull-ups naked to be GIF’d within an inch of his life.

Oh God! I didn’t even think about that! (Laughs) I guess! Ha!

It will be all over Tumblr.

Oh great. Oh man. (Keeps laughing) I don’t know.

As a self-proclaimed introverted person, that must have been an interesting scene to film.

Yeah. (Laughs again.) Once I got into the head space, though. Part of the process was finding the hair and makeup, putting my costume on, and seeing the character in the mirror in my trailer and sort of dropping into the guy. When I dropped into Rudy, I was more extroverted throughout the day. So that wasn’t so bad. But you’re right, now after the fact… My mom’s going to see that! (Laughs again.)

Are we supposed to like or hate the Castor Clones? They’re being painted as adversaries, but they have the same sort of tragic creation stories as the Project Leda girls.

I didn’t approach any of them thinking “What can I do to make people like them?” or “What can I do to make people not like them?” What I tried to do was just try to round them out as much as possible. Like you said, I think people will recognize that how they got there isn’t their fault. So people should feel one way about that. They’ll judge them on their actions, I guess. So if people love to hate them, that’s great. If they hate them, hate them, that’s great. If they love them, love them, that’s great, too. But the challenge of the season, for me, anyway, was getting all these guys and making three-dimensional people. So as long as everyone sees them as people, that’s the big thing. Personally, I think they’re relatable. But I think for the most part there are set up in an adversarial way. So if people look at them like that, I’m cool with that.