NBC’s limited series “Aquarius” stars David Duchovny as a Los Angeles police sergeant investigating a missing person case in 1967. But the real attraction is who’s holding the girl: Charles Manson.

With piercing stares and a hint of something’s-not-right danger, “Game of Thrones” alum Gethin Anthony plays the infamous criminal in his early days of building his flock. Here, the British actor talks “Mad Men” parallels, “Thrones” controversy and, of course, playing America’s most notorious cult leader.

“Aquarius” premieres at 9 p.m. Thursday on NBC. All of the episodes will then be available on VOD.

Did you know much about Charles Manson before coming onto this project?

I knew a fair amount of the famous crimes. I knew they held a mystique over the media. And I was sort of aware that there was something intriguing about how they happened and that he wasn’t actually there; that he had been involved in getting other people to do the crimes. Since the research, I know more about him now.

Did you read prosecutor Vincent Bugliosi’s book “Helter Skelter” about the Manson murders?

The books I started with were “Manson” by Jeff Guinn and “Manson in His Own Words” by Nuel Emmons, which is based on a lot of interviews with him. The key was to sort of get behind our understanding of him as this infamous villain and connect with how he grew up, where he grew up, what sort of instances took place in his lifetime. That was very useful to connect to that side of it.

“Helter Skelter” was a few years after that. It’s on the bookshelf for now. I’ll get to it at some point.

I read an interview where you said there was a certain recording of Manson’s that you used to figure out his voice.

There’s actually an album of music recorded because he was trying to secure a record deal in L.A. There’s an interview he does with the studio engineer and he just talks and gives his perspective on politics and society. That was a very fascinating entry into his headspace and what kind of rhetoric he was employing to convince people he was this bona fide hippie.

And also, it was useful to listen to the cadence of his voice from before he was imprisoned. All the interviews he did after he was imprisoned, he sounds different to me and his body language is different.

”Aquarius” filmed in Los Angeles. Was it helpful for you to actually be in the city where this took place?

That was extremely helpful. Just the basic thing of moving here — so many people I met have either a story about being in L.A. at that time or some connections to what went on. And that helped with the responsibility of telling the story as accurately as we can and sort of filling myself with the atmosphere of California and L.A.

Did you do things like go to El Coyote restaurant, which is reportedly where Sharon Tate had her last meal?

Because our story doesn’t go to that part of the history, I haven’t gone to the places where they were right around the crimes. Part of their story is they were very [nomadic]. They moved around a lot. There’s a whole segment of their history where they go into Death Valley that we’re not up to in our story yet.

They building that they’re based at in the show is based off a building in Topanga Canyon and I’ve been there a few times. It’s a very nice area.

All those more infamous locations, he wouldn’t have been to yet, so I haven’t scoped them out.

Did researching this story and realizing how desperately Charles Manson just wanted to be a famous musician make you almost feel bad for him?

The things he did are certainly evil. I don’t know if I feel bad for him. I’m not sure if that’s the right emotion. But part of your job is trying to understand as much as possible someone’s motivations. That’s part of an actor’s responsibility in any role, whether it’s an ogre in a fantasy show or a real-life historical figure. In that sense, I have a great more perspective than I did on his life and how a human being could be led to doing what he did.

AMC’s “Mad Men” was still on while you were filming and there were rumors about that show’s connection to the Tate murders. Did you follow that?

“Mad Men’s” on my list of to-dos. There’s a lot of binge-worthy series that I have to get to. I’m not too familiar with what was going on there, but it was interesting to me that a great show like “Mad Men” is leaving off around the time that our show’s picking up.

Speaking of binge-worthy shows, I have to ask: Have you kept up with “Game of Thrones” since you left? Do you have any thoughts on the controversy over a recent episode’s [SPOILER] rape scene?

I had a mini-binge [of the series] a few weeks ago. It’s extraordinary television and it’s great that now I get to be an audience member just like everyone else. But I do feel personally invested in it.

I watched that episode and I found it harrowing and I think that’s a testament to how extraordinary the performances were. As for the controversy, I haven’t followed it. But if you execute challenging television, it’s going to catalyze a debate.