What was it about the role that appealed to you?

Tim Roth: Well, it's based on Paul Ekman, who studied body language and the kind of expressions that goes through people's faces and can betray what's behind what they're saying. So, it's kind of an interesting concept. At the time, I was looking for something that would keep me home. I've been traveling so much with work, and I wanted to stay close to my family. So, this came along. I quite liked the idea of playing the character in a long form -- like a play, really. A long run in the West End. I did TV in Britain, and I've worked on a couple of things for HBO and TNT and all that kind of stuff, but I've never done anything like this. We don't even know if this is going to work or not. It's all an experiment, which is kind of fun.

What's the appeal for the large number of British actors (Hugh Laurie, Rufus Sewell, Damian Lewis) working in American TV?

Roth: It seems to me that some of the better stuff is coming out in America now. I was recently back in Europe and watched what was going on our British television, and I've got to say I think the standard is getting higher here and lower there a little bit. The [British] audiences are more interested in what's coming out of the States -- things like The Wire and House and 24 -- than they are in their own homegrown things at the moment. Hopefully, this will help it change.

Did you ever consider playing the character with an American accent?

Roth: No. That was part of my deal immediately from Day One. I said, "I'm not doing that," because, having done dialects and worked with dialect coaches and so on in the past, I'm aware that work level is huge if you want to get it right. So, that was a deal breaker with Fox. They were cool. They were worried about it, and then they stopped worrying about it after a while. I think it's kind of fun. It's not something we even address particularly in the show, although I do come out with some odd phrases now and again.

Can you explain what the other members of the deception team do?

Roth: Gillian Foster (Kelli Williams) is a psychologist/psychiatrist. I can see that there's some deception happening, but if we have to find out why, there are people around me who are in the feelings department. Torres (Monica Raymund) is what would be known as a natural. She just can spot you. She doesn't know why, it's just, "Yes, that's not right." She's just has an innate ability, for whatever reason. There are reasons for that, they think, which comes up later in the series. They're a bit scary, so [Cal] keeps her close. Loker (Brendan Hines) is a research guy. He's more lab-based, I guess. He's doing a radical honesty experiment right now. But he can spot them, too. He's pretty good at it. There'll be more of them, too, I think, people joining up if they keep us around.

In the pilot, Gillian's husband seems to be lying to her, but Dr. Lightman doesn't tell her. Will we find out why?

Roth: That does come up, but probably not in the way that you're thinking... or maybe it does, I don't know. What's interesting about all of that kind of stuff is that people lie for very, very different reasons. The fact that I will spot something or Torres will spot something... what you have to remember is that you don't know what people are thinking. You can tell that they put a deception out there, but you don't know why. So, that relates with Foster's character. I mean, that's going to... spice [things up].

Do you have to watch all your facial expressions on set, because it's such a key part of the show?

Roth: Well, I don't. [But] it's very hard for the actors who are playing the subject. They become very self-conscious after a while, because when you put the camera really closely on them, it's quite disturbing. We have to take them through it. It's quite odd. So, some of the stuff is a little bit too big. We go softer and softer as the series progresses. You'll see. It's quite interesting though, and it's all real. Well, it's not real. It's all based on real.

How good have you become at detecting lies?

Roth: I make a very strong attempt not to get to know too much of the science, and not to practice it at home or any of that stuff, because the real guy, Paul, he can't switch it off. He can't unlearn it. He knows so much about this stuff that he can see, in everybody, what they're maybe thinking. He watches their bodies betray them. I don't really want to do that. I'd much rather just go about my life. [But] I think an audience could really enjoy themselves with it. Paul Ekman is going to do a companion Website for each episode, so you'll actually see the stuff that we're making up and the stuff that's real. Gradually, the audience will learn. You'll be able to train yourself to spot stuff.