[Editor’s note: This interview contains spoilers from the first four episodes of Becoming Elizabeth.] 

Tom Cullen is no stranger to historical dramas, having played a dashing viscount in Downton Abbey, a headstrong Templar knight in Knightfall, and the infamous Guy Fawkes in Gunpowder. But in Becoming Elizabeth, a Starz period drama that chronicles the early life of Queen Elizabeth I, the 36-year-old actor has taken on his most challenging character to date.

In the series, which follows the dangerous scramble for power after the death of King Henry VIII in 1547, Cullen portrays Thomas Seymour, a devilishly charming noble who marries his last lover, the dowager Queen Catherine Parr (Jessica Raine), for both love and power. But when he crosses paths with the teenage and newly orphaned Elizabeth (Alicia von Rittberg), who has moved in with him and Catherine, Thomas begins to eye a whole new pathway to get what he wants. This all leads to a pretty gripping exploration of the sociopolitical and sexual politics of the English court, told through a more modern lens.

“I was absolutely terrified,” Cullen told The A.V. Club of playing Seymour. “I was also intimidated by the writing, because he’s so funny and so witty. He needs to be intoxicating for it to work, and then also tread that balance of him being this kind of very nuanced, manipulative guy. I wasn’t sure if I was able to do it.”

In a recent interview, Cullen spoke candidly about the inherent complexity of his “heinous” character, the conversations he had with von Rittberg and the creative team about depicting the clear power imbalance between Elizabeth and Thomas, and why he decided to respond to online criticism of the show’s first two episodes.

The A.V. Club: You’ve done your fair share of period dramas, so what was it about this take on Queen Elizabeth I’s life that appealed to you?

Tom Cullen: I was really struck by how sharp and funny the writing was. It’s such a cliché when people talk about this stuff, but it felt so contemporary and all of the characters felt so three-dimensional, so fleshed out, and that felt quite rare. I think that it’s quite easy to deify these people, and this felt like the opposite of that. It was really seeing these people as human beings, and it kind of elevated the history beyond just history. Anya Reiss, our showrunner, was 26, 27 when she first started the project, and she was 29 when we were filming it. She’s from South London, she’s got an edge to her, she’s got a punky energy, and you really feel her in the show. I think when she was approached to write this, she was like, “Well, I don’t really watch period dramas,” so I think that she was writing a period drama that she would watch, and I think that that is really quite telling.

I’m British, so before we learn to eat, we have history shoved down our throats, especially Queen Elizabeth I. [Smiles.] She’s so iconic and so much of her story has been told so well and so often, but I was completely unfamiliar with this story [about Elizabeth and Thomas Seymour], and I found it quite shocking. What I found most interesting about it was that whatever happened between her and Thomas, on some level, clearly helped define who she was as a queen, and you kind of reframe her as somebody who really has overcome a lot of trauma in her life to become this very strong leader. I thought that was a very interesting story to tell.

AVC: You’ve said that you had to play Thomas as if he was the hero of the story, because that was the only way you were able to play him without any kind of judgment. How did you come to understand his motivations as time progressed?

TC: I feel very privileged as an actor that I not only get to have the fun of playing this part, but I get to really go into history. I get to really look at one person so specifically and try to humanize them and understand [them] as best as I can—in a way that maybe if you were just reading a history book, you don’t get to do that.

There were lots of things that were quite revealing. Obviously, Anya had done quite a lot of research, and I had to use her interpretation—because that’s what history is, right? It’s just [an] interpretation. Nobody knows what happened, really. It’s a series of documents and writings and anything that’s chronicled, but the bits in between—the human motivation—often are up for interpretation because rarely do people actually write down or say what they actually mean.

It would be so easy to villainize him, and I didn’t think that would really serve the story. It felt too one-dimensional, and I felt like it betrayed Anya’s very three-dimensional, complex writing. So I had to really make him the hero of the piece [and believe] everything that he was doing was just and righteous. I had to really play a trick on myself to the point where on set, I would defend him. I remember when the second block director [Udayan Prasad] came on, he wanted to have really in-depth conversations with all of us about the characters and where we were at, and his reaction to Thomas was so strong, having read the script. And I was like, “No, no, he’s misunderstood. He is empathetic,” because that’s what Anya’s writing is. He is one male character in the whole show who really listens to women and really tries to understand them, but then he uses that to manipulate. And in Elizabeth’s case, he takes away from her what is arguably most sacred to her—which is her innocence.

Later in the series, he especially makes some choices that feel so impulsive. And one thing that [Reiss and I] mooted around was Thomas might have been on the bipolar spectrum. It’s obviously never spoken about in the show, because it would be undiagnosed, and I didn’t tell any of the other actors that this is something that I was playing. But I do have someone very close to me who is on the bipolar spectrum, and I really recognized a lot of his behavior. And just for the record, I’m not saying that the fact that he’s possibly bipolar means that’s why he groomed Elizabeth. He’s a heinous character, but the bipolar [disorder] maybe shows his impulsiveness to act upon his morally bankrupt nature.

AVC: How did you want to portray the clear power imbalance between Thomas and Elizabeth in the first two episodes? It almost feels like the audience is being exposed to Thomas in the same way that Elizabeth is.

TC: Yeah, definitely. I think that Anya had her first ever play at the Royal Court when she was 17, 18, and theater is a very male-dominated world, so a lot of Elizabeth is, I think, Anya [writing about her experiences] as a young woman trying to find her place in the world. In terms of the power dynamic, I think it’s very important that it was [shown] through Elizabeth’s POV.

We wanted the audience to be charmed and fall in love with Thomas a little bit, so that when [he] turns, it’s [as] confusing and difficult for the audience as it would be for the person who was being abused. This is a specific kind of grooming abuse that we’re trying to talk about. I think it shows that abuse [can be] murky and gray sometimes, and that it is often the most charming person in the room who is able to take whatever they want—it’s not always the obvious person you think it is.

Elizabeth is a teenager. She is full of the confidence that teenagers feel when they feel like they know themselves in the world, but also they’re just way out of their depth, and they’re scared and alone. We really wanted to show that she’s confused, she possibly has feelings of love for Thomas, and so she doesn’t necessarily see it as abuse herself at first—that is obviously realized, I think, by episode four.

AVC: In the opening scene of the third episode, Thomas essentially undoes Elizabeth’s dress in front of everyone in the house and chases her around, with Catherine initially participating and then taking a step back. How would you say that was indicative of the complicated dynamic between Elizabeth, Thomas, and Catherine?

TC: That scene actually happened [in real life]. It was one of the most intimidating scenes on the page to do. I was really confused about how we were going to do it, and it could be interpreted in another version that Catherine was complicit in what was happening. Obviously, that’s not the version that we’re telling. But on some level, in the scene, she is complicit, but it’s a moment of realization for her, definitely. It is about two powerful people exerting their power over this beautiful young woman.

AVC: In a rare heart-to-heart with his brother, Edward [John Heffernan], Thomas says, “God persecutes me. I think his greatest trick is that he leaves you still well alone.” What do you think that speech in the fourth episode reveals about how Thomas views his place in the world?

TC: I think the relationship with his brother is what fuels everything that Thomas does. He is so in the shadow of his brother, so belittled by his brother, that everything that he does is fueled by this jealousy. He’s a man [with a] very, very fragile ego and massive insecurity, and I think that he’s so blinded by that that he is unable to see what is in front of him. I think that there’s no question that he and Catherine really loved each other deeply, and I don’t think he realizes how special that relationship is. He’s always searching for more. There’s a hole inside him that he can never fill until his brother’s dead—not necessarily literally, but definitely metaphorically. He has to kill his older brother, and it’s this kind of classic, younger sibling syndrome. [Laughs.]

AVC: Catherine dies from complications of childbirth in the fourth episode, just as she and Thomas were beginning to get back into each other’s good graces. How will Thomas attempt to rebuild his life after the loss of Catherine, and what is his state of mind when he tells Elizabeth to marry him?

TC: When he finds out that Catherine is pregnant and everything comes out about Elizabeth, I think that he sees this as a chance for rebirth for himself, that in becoming a father, he can undo whatever traumas he’s had to [endure] in his life. I think he’s so happy and willing to do that. And then Catherine’s death pulls his whole world apart—a huge void is left. He is just utterly lost. His brother and his wife have multiple children, and [his sister-in-law] still lives, and his brother just always wins. And everything that Thomas touches, he feels, turns to dust, even when things are turning a corner for him. He obviously doesn’t see his own contribution to the fire when everything turns to dust—he blames everyone else.

But this is where I really started to play that Catherine’s death really triggers his bipolar [disorder], and he goes into a massive downswing and has a really nasty episode, and he’s very fragile. And as the show progresses, he definitely goes into an upswing and starts to act very chaotically. He isn’t thinking things through, and I think that he’s searching for somebody to take the pain, the grief away. He’s searching for somebody just to fix him, and that [burden] lands upon Elizabeth. It’s quite violent and chaotic, and it’s quite awful for everyone involved.

AVC: What kinds of conversations did you have with Alicia about the cat-and-mouse dynamic between your characters?

TC: I was so nervous about who I was going to do these scenes with. It really had to be a very trusting relationship; it had to be one where we could really rely on each other and have a real openness and camaraderie, because the stuff that we’re playing is really not pleasant. Alicia and I really bonded very quickly and we got on very well, and [we have] a lovely relationship with a lot of respect.

Our conversations were often about levels and gradients: How far do we need to push this? How awful should it be? And we both were playing these kinds of mind tricks on ourselves. I think that she really loved Thomas while we were filming, and she would also defend him because she really went quite deep in the character. So our conversations were definitely about trying to figure out the nuance and really tread that line as well as we could. Everything was discussed at great length at all times—we had a lot of meetings with directors and the writer.

Anya was on set all the time as a kind of sound board, and she was very vocal as well if she felt like we were missing [the point]. But then in the scenes themselves, there was lots of room for exploration, and [von Rittberg] is a very exciting and responsive actor. Anything that you kind of throw out there, she really takes it on, says yes to it and plays with it.

AVC: After the second episode, you left a comment under a YouTube video, in which a viewer was describing how disappointed she was with the show’s depiction of Elizabeth and Thomas’ relationship thus far.

TC: I never would normally do that, and I actually really enjoyed that fan interaction. I found it so moving to see people feeling so passionately about this storyline, but I was also really hurt, because it’s a story I deeply care about. That video specifically was getting a lot of views, and she said that we were kind of basically throwing the #MeToo movement under the bus, which is the complete opposite of what we’re doing.

I think that people were expecting Thomas to be this villainous, quite archetypal bad guy, and that isn’t the story that Anya wants to tell. I think that this specific abuse that we’re telling [in] this story is a lot more insidious than that. And because it’s insidious, it takes time, and I just really want the audience to stay in there and watch it, because I know that they’re very righteous anger would be vindicated. It was a really nice interaction, and I’ve had lots of really lovely messages, and I’d like to do more of it, to be honest.

I think that it’s also a testament to the show and to Anya’s writing that it has sparked such debate and such polarizing opinions. Some people can really see the grooming for what it is, and some others can’t. They are definitely inside Elizabeth’s mind, where they’re seeing it as romanticized, which is, to be honest, quite astounding to me, because he was clearly quite a violent guy, especially in episode two. There isn’t anything romantic about it. I see a very scared, young 14-year-old girl who feels very lost, and the one person that she felt safe with has suddenly become arguably the most dangerous, and she feels a lot of feelings of love but also fear. So I was defending the show for sure.