Your singing in "Hunky Dory" is really quite impressive; you hit some crazy highs. How long have you been singing?

I've been singing since I was about 10 years old. At about 11, I started acting. I took it very seriously and I used to do lots of singing. And I got a few record deals in the UK. Got a lot of recognition with my voice. But I decided against it. Music's very personal to me and it's very intimate. The trouble with the music industry now is that you don't get to decide what you want to do. Labels command you instead. Back in the '60s and '70s, you could create your own record label or write your own stuff in your basement. It was so much more accessible. But now you're kind of commanded by a hierarchy and you're puppeted with your talent instead of in a creative environment.

The whole process of "Hunky Dory" was wonderful in that sense, musically. All the kids in the orchestra were playing the instruments. The choir was actually singing every song. Every actor in the film sang everything live.

It was a long process. We started when I was 18. I did a workshop for "Hunky Dory" and we had our first orchestra [session]. The musical director and the composer were there. We had a few songs and a few other people that are not in the movie, just singers. We just jammed for four days solid playing every song we could think of from '70s and had an amazing time doing it. And through that, I think we found the genuine, fluid natural environment of how music is. I think that's when the decision came to do everything live and not record in a studio. We realized that we could do it live and it had a raw richness to it. It was a smudged beauty. We embraced that and kind of ran with it and made that the key special element.

Aneurin Barnard in "Citadel"
Cinedigm Aneurin Barnard in "Citadel"

Moving onto "Citadel," how close were you and director/writer Ciaran Foy on set, given the fact that he suffered from agoraphobia as well?

Ciaran is one of the best directors I've worked with and such a genuine lovely guy. And for this to be his first feature is just incredible, I think. His first feature straight into a festival!

It's always important for me to be very close to the director. When you're working on something which is very personal like with Ciaran -- he suffers from agoraphobia -- it's very insightful. I've got him as a free gift. His tales are free for stimulation. So it was very important that we could just talk about anything at any moment. And it was tough. I kind of lived that for two months; very long days.

I talked to Elizabeth Olsen about her work in "Silent House."  She was also tasked with maintaining an unrelenting fear of her environment. She talked of bringing the role home with her at the end of each night to the point where she suffered from nightmares. Was that the same case with you?

Yeah, I had no choice, you know? The days were long. 12, 14, 16 hour days sometimes. Also I was just sitting in a hotel on my own a lot. I'd have one drink at the bar at night just to settle the nerves, try to switch off.

I'm not a method actor, but I wouldn't say I'm not, either. For this role I really did jump in there and lived it a little. It got to a point where I would go to the gym. I'd finish filming and I'd go straight to the gym and just run for an hour and a half; just completely exhaust myself out. Probably not the best thing to do, but they didn't have to use much makeup on me then because I was actually unbelievably tired and worn out. And hopefully it added to that element.

Fun fact: You and actor Tom Cullen studied together at the Royal Welsh College of Music & Drama. He broke out last year at SXSW with "Weekend" and now you're following in his footsteps. Coincidence?

Yeah. It's funny because I was in the year above Tom.

Did you go to him for any pointers on how to handle the festival?

You know, you kind of just have to embrace it, I think. The nice thing is Tom knows that I've been in these positions before. It's funny because Tom asked me things…

Before he came here?

Yeah, 'cause I left two years before Tom and went into the business. It's nice when you can tell a friend how to do it.