I had this extraordinarily bizarre moment when, two Fridays ago, my missus gave birth to our second child at 11am and by the same time the following day I was sitting around a table with Ridley Scott, Russell Crowe and Leonardo DiCaprio in Rabat in Morocco, rehearsing a scene we were going to shoot the next day.

Interestingly, this character [Doctor Nash] is probably closer to me than somebody like the evil Sir Godfrey in Robin Hood or Lord Blackwood who wants to take over the world in Sherlock Holmes. This is a character that's English, he's based in London, and so it's closer to me than a lot of stuff I've been doing recently.

I think it serves the purpose of the film if the premise is that you're unsure of me because you've only ever really seen me play villains.

All these portrayals we see of knights fighting must be absolute rubbish because knights in armour could literally have only had two or three blows and then they'd have had to sit down to have a cup of tea.

I loved making The Imitation Game and it's really gratifying to hear the audience's response to the character that I play. It was just a little thing that I did because I really liked the film and I liked Benedict [Cumberbatch] and I loved Morten's [director Morten Tyldum] previous film, Headhunters. For me, it was something I did thinking, "Wow, this is a lovely quality piece of work."

In the movie, you have to decide as an actor how you are going to give a character presence. You can't really move, walk, and talk like yourself. This creates something so you have to find something "other".

The idea of transformation - playing something I'm not - is the bit I enjoy most about acting.