Michael Sheen has made a name for himself playing real-life characters, from Tony Blair in The Deal and The Queen, to Kenneth Williams in Fantabulosa!. This week sees the release of his critically acclaimed turn as David Frost in the screen adaptation of the play Frost/Nixon, while he will soon be seen playing football manager Brian Clough in The Damned United, which hits UK screens in March.

In the heat of awards' season, RT caught up with the actor to learn more about Frost/Nixon, his acting process and the challenges of bringing a play to the big screen.

Were you worried about losing some of Frost/Nixon's live tension in the transition from stage to screen?

Michael Sheen: I was worried about whether it would work at all on film, let alone with tension. Just because something works in one medium... that almost ensures that it won't work in another. So there was no reason to assume it would work on film. Doing the play it progressively got bigger. We started at the Donmar, which was actually more like the film version in a way because it was much more intimate. Then it got bigger and bigger and bigger. So I knew we were going to have to let go of what we'd done on stage and re-discover it on film, not just repeat what had worked on stage. And I suppose because it was me and Frank [Langella] in the film as well as on stage, the rhythm or sensitivity that we'd built up to what each other was doing really paid off.

What did the camera change?

MS: The camera coming right in there added more tension, if anything. We kind of trusted everything we'd built up over 350 odd performances, a lot of which the audience actually wouldn't see. A lot of the detail that was going on on stage towards the end the audience wouldn't get, but it's there and the camera picked it up. So I think you start to see on film a bit more of what's going on underneath. The eye movements, little hints that everything's not as OK as it appears on the surface, that you can't get on stage because you're just so far away.

Did anything specific change in the transition?

MS: The cast did, which was one of the major things. When you've got a new group of people around you, it makes it a lot easier to re-discover and make it fresh again. You get so used to the way the actors say the lines on stage that you can get stuck in a rhythm of how you do what you're doing. But you've got a different actor in front of you, giving you something completely different, and suddenly you hear it different, and then your reaction is fresh again. That was a huge element of re-discovering the piece.

Can you tell me a little bit about your relationship with writer Peter Morgan - are you involved with the creative process at all?

MS: I'm not involved in the original writing process. He'll usually send me a very early draft of a script, I'll read that, and then we might do a reading of it because he likes to hear it, and then based on that reading he'll go away and re-work stuff and we'll talk about it. We talked a about the Clough film [The Damned United] a lot before he put pen to paper. We both read the book and talked a lot about where the story could go, because he has to choose what he's going to focus on, so we talked about all sorts of different thing. But ultimately he goes away and does whatever he wants to do, he doesn't have to take my advice or anything. But once we've done a reading, and we're coming closer to rehearsals, then it starts to become a more fluid process. He'll have his laptop with him and he'll hear me doing a scene and he'll immediately be re-writing based on what I'm doing... taking it in different areas. So it immediately becomes very responsive at that point. I wouldn't say I have anything to do with the writing, but the way he writes becomes very organic and in the moment.

Is he involved in your acting process then?

MS: It carries on to set - he'll watch me doing a take and tell me what does work and doesn't and swap things round. Like Peter says, a lot of actors don't like that, but I enjoy that side of the process - him responding to what I'm doing and then me in turn responding to what he does. It seems like a good way of working.

Playing a lot of real-life characters, does your research and preparation change from character to character?

MS: The process itself is exactly the same - I get all the material I can get - footage, books, talking to people. I immerse myself in all that for maybe a month - I don't even try to do anything else, I just surround myself with all that. Then I'll start to get ideas... for instance, something that you wouldn't immediately think of as research, is for Clough I started looking into cult leaders, because the way he worked with teams was that he created a cult. There was total worship of him, total obedience, he worked off charisma and fear and all that sort of stuff. So I might go off on a slight tangent.

Then how do you get back to the character?

MS: I start working with a lady called Penny Dyer [a voice coach], who I work with on everything, and we start talking about why someone sounds the way they do. It's about trying to get inside. It's not about the external parts of it, it's about trying to get where it's all coming from. How I can use all the external things to point inwards. It's like those religious paintings where people are always pointing up, at God, because it's what they want you to focus on. And I want everything - the voice, the mannerisms - to be pointing in, so that the audience aren't watching it for its own sake, saying 'Oh, isn't he like so-and-so'. That hopefully doesn't even become an issue, so that everything is about revealing character, and what is going on underneath. That's why I've got to get to the point when I'm actually filming, that I'm not thinking about how like the person I am, it's just about doing scenes like you would with a fictional character. Because if I'm not thinking about it, hopefully the audience isn't.