So this series is all about your character Theon Greyjoy apparently... "Yeah everything. The whole thing. No it's cool, the first series is more of a background role for me but then I come to the fore and I definitely have an interesting journey so I'm hoping I can make a good job of it."
Where does Theon fit in season two? "I don't know how much I can talk about it, I know it's in the books anyway, but we try to keep it secret for those who haven't read them. I basically get sent back to Pike to form an alliance with my family and things go kind of alright for him, but he's got a big identity crisis.
"When he leaves the Starks, he's trying to be a Stark, but when he goes back to his family, the Greyjoys, he realises that he has to prove to them that he is a Greyjoy. And he makes all these wrong decisions just trying to prove himself. I guess everyone can relate to that, can't they?"
What's the reaction from Thrones fans been to the first series? "Pretty good, I don't really know about on the internet or stuff like that, but people I know, people have just been really pleased with it. People who I didn't really think would be into that sort of thing loved it and I'm very, very pleased with that."
Did you know how huge it would be? "No idea whatsoever. It was only when I realised how huge an impact the books had that I started to grasp, 'Wow, this is pretty huge'. In a way that does add a little bit of pressure to yourself because you just want to do things correctly for the fans who are so into the books. But sometimes some people can find it a hindrance having it down as a blueprint because you have to make it your own. We definitely have a license to make it our own so we have stuff from books and then stuff that we've brought in as actors."
Watch a trailer for Game of Thrones season two:
It's really dark in parts. When you read the script did you raise your eyebrows at any point? "Definitely yeah. It messes around with your moral compass because you don't know whether you should be going, 'Woah, I dont know if I can watch this' or, 'Yeah! Come on!' It's pretty full on but that's all part of it."
Do you know what eventually happens to your character and are you looking forward to it? "I don't know. People have kind of said this sort of thing to me, so I know there's something big. It's not that I want to keep it a surprise or not ruin it for myself, I just don't want to think about it too much. When it gets round to that point I might read it a couple of times. If I read it now I'll be thinking about it for too long. I want to read it, but I kind of think it's healthier if I don't."
How does the Thrones fandom compare to Harry Potter and Twilight? "I'd say there aren't as many screaming girls. That can be a good thing and a bad thing. I'd say it's more for people who are into good stories. I mean, Harry Potter's a great story. Twilight I don't really know about to be honest."
How does the scale of budget compare to previous projects you've worked on? "The amount of extras is unbelievable on this show. I've never worked on that sort of scale before. The sets were incredible, the studio stuff was amazing and the stuff they find in Northern Ireland and then eventually all the stuff from Croatia... it's insane.
"I've worked on big budget films before but this was sort of different. The first day when I walked on set, there was this huge set with all these soldiers and extras running around. And then there are like four cameras on the set when usually I'd be working with one, so everyone was like, 'Please be careful with that!'
"It was definitely interesting. It didn't make me freak out, if anything it made me want to get on with it and enjoy it even more."
There's a huge cast and big names - who have you enjoyed working with? "Richard Madden, I loved to work alongside him, he's a very funny man. Kitt, we didn't have much to do together, we're just mates. Meeting Peter Dinklage was just great. I had one scene with him in the first series which I was ecstatic about. I would like to, not work with, but get to know Charles Dance because I think he's just a genius.
"But also in the second series, working alongside Patrick Malahide is brilliant. And Gemma Whelan who plays my sister is brilliant. There's another girl, I don't know if I can talk about her and reveal her identity, but she was great as well."
What has your family's reaction been like, do you watch it together? "No not really, we don't watch it together. But I definitely get feedback, they're very, very happy with it. There was one point where I was with my mum, and that scene came on where Ros... there's just this really graphic lesbian sex scene and I was just watching it with my mum, so that was quite funny. We don't watch it together, but I'm definitely getting pats on the back which is good."
Could British TV ever compete with a show like this? "Definitely. It's not about the money, it's about the content. There's stuff out there that costs 100 grand to make that is just as moving, just as intense. I think definitely British TV can rival it for sure. It's great when you see things on a massive scale and you see these huge sets, but it's not the be all and end all - it can be about characters as well."
Do you think Game of Thrones will be held in as much reverence as other HBO series in five years' time? "Definitely, yeah. With those sorts of things it takes a while anyway because people don't really sit down and watch it, people like a box set. HBO is very smart in what they're doing. They're releasing DVDs just before the second series so people see the advertising for the second series and watch the first episodes of the second series and go, 'Oh my God I've just got to watch the first series'. It can be a slow burner, like with The Wire, which took a while before it actually blew up over here. Definitely it will be held in the same high regard."
The show is very complex and hard to pin down. How would you sell it to viewers? "It's... oh god, I don't know... I'd just say it's... Don't go into it thinking it's going to be about wands or dungeons and dragons and all of that. It's way, way deeper than that.
"It's all about the politics and what's going on in this land. Don't go into it thinking it's going to be a Lord of the Rings style thing because it's not. It's completely different. Not that Lord of the Rings isn't interesting, I just find this far more interesting."
Game of Thrones season two premieres tonight (April 2) at 9pm on Sky Atlantic. It continues on Sunday nights on HBO in the US.