To say that they both play characters who are rather, well, intense is a bit of an understatement — given that one’s a drug (and power) addict and the other’s a serial killer who thrills in torturing women. But in person at Variety’s Actors on Actors studio, Michael Kelly (Netflix’s “House of Cards”) and Jamie Dornan (Netflix/BBC’s “The Fall”) were only too happy to shed those dark on-screen personas. Clearly fans of each other’s work, they shared their secrets of finding humanity in those indelible roles.

Michael Kelly: What do you look for in a part?

Jamie Dornan: I think in recent parts, it looks like I like to play really creepy psychopaths or sociopathic people, but I love the idea of just really exploring a side of myself I haven’t explored before. I feel like I’m a million miles away from (character Paul) Spector, but I’m pleased to say that I’m a milion miles away because he’s a psychopath. I think you discover so many things about yourself as an actor. It’s one of the cool things about what we get to do, by getting into the mind of characters that are so far from you, you discover things that maybe you don’t want to know about you that scare you about yourself, or you never realized that you possessed. I think that’s really interesting. But I don’t go looking for specific parts.

Kelly: Do you find it hard to leave that character? You go through a 12-, 14-hour day. Do you end up carrying it with you?

Dornan: My sole intention is to leave it on set, and I’m intrigued to know about your process with that. But I like to try to leave it behind and pick it up the next day. But someone like Spector, who is so all-encompassing and intense and it takes all of my energy to play him, he’s a hard one to shake at the end of the day.

Kelly: At least the core of it, right? Even between setups I can totally joke and whatnot, but part of it’s going to stay with you.

Dornan: With the second season of “The Fall,” I sort of scared myself by how easily I could slip back into him. I’m not saying it was less work or the challenge was less, but I did find it easier to inhabit him having done it for a season. But is that the same with you and Doug Stamper? Can you just slip back in?

Kelly: In season one, Beau Willimon said, “I don’t want you to emote. That’s the main thing. For the whole year, just don’t emote anything and I want everyone at the end of the season to be like, ‘What the f–k is up with that guy?’” So then for season two we found out a little bit more about him, but I was already him. The character was basically created from that one note, which really made that persona. And it certainly became easier. The third season, obviously, he was actually a different person almost.

Dornan: I made a choice with Spector to play him very still, and that was interesting what you were saying Beau said to you. I love the idea of that one thing the audience just goes, “What is going through his head? What’s he thinking?” Allan Cubitt, who created “The Fall,” is so smart at creating moments where you spend a lot of time with Spector when he’s alone, which I think is interesting because as an audience member you’re sort of gagging to find out — gagging is an interesting choice of word, actually — but you’re desperate to find out what is it that drives these people, so something I really wanted to achieve with him was the stillness. And (your character Doug) Stamper, it’s such a similar thing that you were saying, like that intention that Beau and you worked out, it works so well. And then the third season, you really do explore it and see what is driving it beyond everything else. It’s fascinating.

Kelly: I felt the same watching yours, and the obvious common thread that you were just talking about that both of us had — you’re alone for so much of it. I don’t know about you, but I found it to be so much harder than having someone to bounce off of. You’re constantly questioning. Because, in my opinion, half of acting is reacting and listening, so there’s nothing to listen to.

Dornan: It’s totally a different challenge, isn’t it? I find it kind of comforting to spend time by myself especially when I’m playing Spector because he is so internalized and such a loner of sorts, so to manifest the ideas that he has and create the world that he has in his head, you kind of need to be alone to be doing that. But I enjoy that solitude because I have an awareness when I’m doing it that it must look pretty creepy. It becomes quite creepy watching someone try to be that kind of monster. To spend time with that person alone I think is really intriguing, and there’s an awareness of that when we’re filming that I really get off on when I’m doing the stuff by myself.

Kelly: For season three, when we started, Kevin (Spacey) was doing a play in London, so I think I shot for two weeks totally by myself. The first two weeks of filming, that whole recovery process was all alone. And it’s funny that you said “comforting,” because for me it was like, I had to find and be comfortable. I found it to be a real challenge to not have someone to play off of. The best way that I could approach it was I had to be so relaxed and so comfortable to do it. After I had done all the crazy research on brain injuries and how people act, thank god I had that month and a half prior to filming to learn about all that stuff so that when I got there, I could just be in it. Beau Willimon was like, on that first script, “So, what do you think?” And I was like, “I’m scared to death, dude. I’m really, really scared. You don’t leave me for 30, 35 pages, and it’s the first 35 pages, other than that page and a half of Kevin.” And he was like, “Dude, you just gotta hold the audience who’s loved this show for two years. It’s all on your shoulders. No big deal.”

Dornan: Those moments when it’s Stamper’s darkest days, it’s so beautifully shot. It looks amazing, even going onto the sets and the lighting and the sparseness of it. That just helps so much. It really sets the tone.

Kelly: We have an incredible art department and construction team. They’re amazing. Obviously that was the first time we saw Stamper’s apartment. And I was like, “It totally makes sense. That’s exactly right.”

Dornan: That comforts you massively, because they’ve done their work so well. Often you’re on the page and you go, “I just don’t know how I’m going to sell that.” And then you get there and you realize that you’re not the only person who’s got the script and went, “OK, how are we gonna pull this off?” There are so many facets of the business that help you out and set the tone. It’s so important. Was Beau very honest with you about where you’d go with Doug?

Kelly: He’ll give you little pieces. He gave me my overall arc for season one, which was to not emote, and that set the tone for the character. And then beyond that, he doesn’t even know sometimes. They have overall things they work on, overall storylines in the writers’ room. But the really interesting thing about our show is something happens and Beau Willimon takes that and goes “Hmm, OK. This happens, so now this is gonna happen, so now this happens.” The best example of that is Rachel Brosnahan who plays Rachel Posner. She was “prostitute.” That was her character name, and she was only going to be in one or two episodes.

Dornan: My wife and I were wondering if they had a plan for her.

Kelly: No. Literally, she was going to come in and help me take Russo down. And she was so good with Corey (Stoll), they had great chemistry. Then she and I started to film our stuff, and it was like, “Well, that’s really interesting.” So Beau went and wrote another scene and then another scene. And then Beau was like, “What do you want your name to be? How about Rachel?”

Dornan: That works!

Kelly: Such a talented young girl. That’s what was so hard about this season. Because the finale was actually written that I let her go. And then Beau came to me, and said, “I’m thinking that you’ve gotta kill her.” It literally happens as we go along. That’s the greatest thing about Beau. He doesn’t sleep. He’s there for every first take, every rehearsal, and then he just goes back to his trailer and writes all day long. He stays up all night. I don’t know how he does it. What about you? Beau will say, “If you have any input or something you wanna get into with Stamper, let me know.” And I’m just like, “That’s on you. Just tell me where to dance. I’m a little monkey. Dance, monkey!”

Dornan: Yeah, I’m very happy to be the monkey but actually Allan Cubitt, our creator, he’s an astonishing human being with the most incredible mind and I owe him so much. I definitely hadn’t done enough work really to warrant being given that opportunity. I had never even done a small part in a BBC production, nevermind being given a lead. So it was a big punt for them to take on me, and that was all driven by Allan. He was like, “He’s the guy.” I know he had to fight for it and it automatically did wonders for how comfortable I felt early on. So as nervous as I was in the first couple of takes, he was just great at going, “It’s OK.” And when I didn’t get fired after the first day, I was like, “OK.” At the table read, I was like, packing up my bags, this is not going to happen.

Kelly: You’re like, “Get through the table read, get through the fitting, and then get through your first day.” And then still, you’re like, “All right, let me get through the first episode so that they have enough tape where they’re like, ‘It would really be a pain in the ass to recast.’ ”

Dornan: I’m terrible at table reads. The things I’m most fearful of are auditions probably, and table reads, because I’m always like, “Don’t judge me on this.” It’s when you see the creative people, the producers and the director and all, go off to have their little meeting after the table read, and you just wanna sort of pop your head in and go, “Guys, come on. Don’t be judging. By the way, on the day, I’ve got this.”

Kelly: They’re always like, “We just want to hear you read it. Don’t act, just read it.”

Dornan: Everyone is so brilliant on your show. Are there any other actors who you admire, or admire their choices?

Kelly: Ed Harris, I think, has made the greatest choices; he does the most interesting work. He’s this bad guy quite often that you like, sort of like our crazy characters. There’s just something about him where he’s always so present and without ever saying a word. He’s just someone I’ve always looked up to and really admired and been like, “That’s the mountain that I see. I want to get to that.” How about you?

Dornan: Yeah, I have a plethora of choices. “The Fall” came to me when I was 30 and I’m happy that I was 30 and not 20, because a lot of it happens to kids who are 20. I didn’t get a great deal of work and experienced quite a lot of failure in this field. So I actually admire a lot of other actors who that was the case for. Guys who it didn’t quite happen for in the way that maybe it does now, like Michael Fassbender, who’s such an astonishing actor, but 10 years ago was obviously not where he is now. George Clooney, Anthony Hopkins, there’s so many of these guys who it didn’t happen early on. I have a sort of deeper understanding of those guys, weirdly, and I admire them more for that.

Kelly: I’m the same. For me it was always these baby steps. Had it happened in my 20s, I would have blown it.

Dornan: Think about some of the idiotic stuff you did in your 20s.

Kelly: I was crazy, dude! Me, particularly, I was an idiot. I was playing in bands in New York City, drinking, just insane. So I’m glad as well.