New York cops are very specific in terms of the way they talk and the way they handle themselves. All these cliches that, as an Englishman, I thought were from a bygone era or were a bit of poetic license with cop shows - the more you hang out with them, the more you realize how real that jargon is.

What made me want to be an actor? Ah, I'm not really sure, to be honest. I was one of those little kids who did it around school, and then I got to university and made lots of bad plays and short films, and then midway through that, it suddenly dawned on me that this might be a satisfying way to earn a living, if that was at all feasible.

I was in the school plays, I did a lot of music. I carried on through university for short films and loads of plays.

I don't think I believe in ghosts, per se. But, my nearest experience was when I went on a weekend away and was in a bar in England, years ago, with an ex-girlfriend. I heard this scratching. I was about to go to bed and I was thinking, 'It's an old ghost.' I could hear this noise, but I couldn't work out where it was coming from.

I think you can tell when a New York show isn't shot in the city. It's so iconic and has such a specific energy.

What I like about the 'Underworld' thing is that it's a mix of cool genres, as well as creating its own message.

What is interesting, as well, is how much power homicide detectives have and how much respect. They are kind of rock stars, especially in New York. There are not that many of them.