“We were like: Matt Smith would be interesting,’” recalls Miguel Sapochnik, showrunner on HBO’s Game of Thrones prequel series along with Ryan Condal.

“Then it was like, ‘We should come up with some names — Matt Smith would be interesting.’ Then later it was, ‘Well, we should probably go to Matt Smith at this point.’”

Condal: “I was big fan of The Crown, and Matt’s performance in those two seasons told me everything you needed to know about the actor–he can disappear into those roles. Prince Philip shares some crossover traits with Daemon.”

Critics and fans have singled out Smith’s performance as one of the strongest draws of the new series, which debuted to a record 10 million viewers Sunday. Yet the 39-year-old British actor wasn’t immediately sold on joining the show.

Reaction when first approached?

I was in a car park and my agent said, “There’s this part in this new show that is a prequel to Game of Thrones.” And I was like, “Ohhh. I don’t know. It’s a tough one, isn’t it? It’s a tough one to follow. Haven’t we seen this before?” But then [the offer] sort of didn’t go away. Then it came up again, and then I went in for a screen test and then that was that.

What convinced you? 

I became aware that Paddy Considine was doing the show as well. He’d already been offered the role of King Viserys, and I was such huge admirer of Paddy’s and I’d always wanted to work with him. So that was a real draw.

And then there are so many elements to Daemon. I love the relationship with his brother. He’s a brilliant character because you never quite know what he’s thinking. I liked the ambiguity of that. There’s a ruthlessness in his personality that I thought was really interesting to see characters who behave that badly. But in many ways, he comes from what he thinks is quite a genuine place.

That’s one’s job as an actor, isn’t it? You have to disappear and you can’t really listen to outside noise. I learned that with Doctor Who. It was such adverse reaction when I first got that part, and you just have to shut it out and focus on the work. I always knew I could add something to it. It won’t be to everyone’s pace, I’m sure. But I certainly feel that I’ve made a connection with Daemon and with the other actors as well. I think we’ve got a wonderful cast.

Actors from the original series?

I had a brief conversation with Daenerys Targaryen actor Emilia Clarke. She was very generous. But this was before my screen test. So it was all a fresh experience.

Old-school Targaryen prince?

I said this to at the start that I don’t just wanna make it this one thing. On the page, Daemon could really be one thing. I was interested in trying to subvert it a little into something else. There’s a sort of strange, sensitive nature to Daemon and quite a genuine loyalty to him and humanistic qualities that you can peel away and see.

Biggest challenge?

There’s a lot of stunts involved, and that was challenging over quite a long period. It’s a big 10-month shoot. Physically, it was really draining. But there are those big scenes where you sit around the table that are quite challenging because there’s so many characters to cover and it takes days and you’ve got to remain sharp and focused.

That was doing a stunt in a helmet. Hit the disc in my neck in Portugal. It’s fucking pain in the neck–literally, metaphorically and physically.

Recovered now? 

I’m actually waiting to go into the physio right now after this to do some work on it. But, you know, it’s all part of the process on some level.

Getting into character on the set?

I had wonderful moments of real focus and engagement with Rhaenyra Targaryen actor Emma D’Arcy and with Paddy where we would just totally be locked into one another’s energies for the day. We could still have a little laugh or whatever, but when the camera was rolling, the focus was on. Yeah, it felt very real. I wouldn’t call it “method” — that’s such a hard thing to do over the course of 10 months. But that process does bleed in and out if the other actor is up to it.

Daemon’s relationship with his dragon? 

Really interesting. There’s a kind of weird symbiosis, like with an avatar. Caraxes is really grumpy. There’s a similar cantankerous nature to both of us.

There was wind and rain and it feels giant motorbike. It was fun. You’re quite high up. It’s not a bad day at the office.

Reputation of Thrones still a concern? 

We’re all aware of the cultural footprint and the phenomenon that was Thrones. It was its own thing and it was in its own time and it was brilliant and it will be impossible to replicate or recreate that time. All we can do is focus on the show twe are trying to make, and while it belongs in the same world, hopefully, it will evolve and become its own thing. This focuses on a tighter group of people, and Thrones was immediately much broader in story terms. This feels like more of a family drama. It’s never gonna recreate the levels of success that Thrones had because it can’t–it was totally original moment. But we’ve tried to create something that feels entertaining in a similar way but will take on a different identity.