Right now as the final edits of the second season are still being cut, Cox doesn’t know what will happen to the majority of the other characters in the show. With a production this big it’s impossible to keep tabs on everything that’s happening unless you’re the producers or the writers -- and they’re famous for keeping all that information to themselves.
Meanwhile for Cox, the opportunity to act alongside a legendary director like Martin Scorsese and actors like Steve Buscemi is both exhilarating and nerve wracking.
“All actors at some level want to be acknowledged for what they do and I’m no different,” says Cox. “It’s exciting to think that this may lead to other opportunities but I’m not going to get carried away by it.
“People told me I’d be on easy street back in 2007 with Stardust and that didn’t happen. The fame and fortune thing is nice as far as it goes, but it used to be you got famous because you were talented and that’s not quite the case anymore,” he adds sensibly.
Cox shies away from any further plot scoops into his upcoming season, but he will happily admit that he researched the activities of the IRA unit founded by Michael Collins that was known as The Squad or the Twelve Apostles.
These men, hand picked by Collins himself, acted mainly as assassins and they targeted policemen, collaborators, civil servants, MI5 members and most famously the so-called Cairo Gang (a British intelligence group who had formerly served in the Middle East).
“I was fascinated to learn about the history of that period, and it really brought my character’s own background to life for me,” says Cox.
“Once you start delving into that you get a real sense of the period and the stakes in play. And I have to mention the costumes and sets. They’re so well done and so meticulously researched they do so much of the work for you.”
As a lifelong rugby fan with his own seats at Twickenham, both Cox and his father thought they might have taken the research into Ireland too far when they started cheering the Irish rugby team in its match against Australia recently.
“My dad was suddenly standing up and shouting, ‘Come on Ireland -- I mean England!’ at the television and we both started to laugh at the level of involvement. Maybe this character has taken over our lives.”
Boardwalk Empire broadcasts on HBO, Sundays at 9 p.m.