5 minutes with: Robert Sheehan – 'The script for Wars of the Roses looked like an encyclopaedia'

I proved myself to be a show-off little twit by the age of about nine and half. I played the main part in a play in primary school called Oliver with a Twist and that was my first foray onto the stage and my foray into acting.

When I was fourteen there was an open casting call on television for an Irish film called Song for a Raggy Boy. I said to my mum "I'd love to audition for that" and she patiently took me along. I eventually got a small part in the film and then [after that] got an agent so that was the beginning really.

I did a movie in Belfast called Cherrybomb with some actors that I knew: Rupert Grint and James Nesbitt. I got a central part and I thought "wow this is good". When [Season of the Witch] with Nicolas Cage, Ron Perlman and Christopher Lee came along straight after that I realised, oh actually, I'm working at a good level here and if I don't maim myself in a tractor accident I think I will be able to maintain this. And so far I've managed to avoid all agricultural machinery.

It doesn't annoy me when people associate me with Misfits. Not at all. Thankfully any sort of approach that I get is unanimously lovely. And then I make it weird.

The Wars of the Roses was adapted from Henry VI Parts I, II and III and Richard III by old Bill Shakespeare. Back in the early sixties, John Barton and Peter Hall quite valiantly and somewhat insanely took those four plays and adapted them down into a trilogy which you could come and see in a day. You'd see the ebb and flow of the tide of power. There's a poetic sentence that just came out of my mouth.

The process became very focused, very fast paced. Which is great because sometimes, even if there's a troop of very good actors, if there's a pensive Shakespeare piece it can be difficult for the audience to maintain focus. The pace was all Trevor Nunn because the script looked like an encyclopaedia when it arrived. We [all 23 actors] have to completely trust Trevor implicitly on this because otherwise there would be too many cooks spoiling the Shakespearian broth. It's been really lovely to be working with a genuine class act.

The great thing about the project is that you meet Richard in the second play, Edward III. It's the first time we see a young, gleeful, mischievous Richard, so to go from that to a completely fascist dictator, I mean, it's a lot to take on. But that's what Trevor's been compelling me to portray, that young sort of teenage Richard who starts off as an innocent.

I'm going to do a film with Hailee Steinfeld next. Screenwriter and filmmaker Dustin Lance Black has adapted a book called The Statistical Probability of Love at First Sight. It's a two hander about love. It's a really, really interesting script so, if all goes to plan, that'll happen after we finish this.

The Wars of The Roses runs at the Rose Theatre, Kingston until 31 October 2015.