Sometimes reality can intrude on docudrama. Michael Sheen, who plays Tony Blair in “The Queen,” Stephen Frears’s history-based comedy-drama about the PM’s relationship with Elizabeth II (played by Helen Mirren) in the days following the death of Princess Diana (during which he prodded her to break with the royal tradition of stoicism and give her people the show of grief they demanded–and perhaps saved the monarchy in the process), visited Dallas recently and recalled filming some scenes at an estate adjoining the royal castle at Balmoral in Scotland.

“There was one shot that got ruined because the actual royal family went past on the top of the hill,” he said.

“The Queen” is the second time Sheen has played Blair. The first was in a 2003 British television drama called “The Deal,” also written by Peter Morgan and directed by Frears, which focused on his ascendancy to the leadership of the Labour Party. Sheen it described it as “a benchmark in British television, because it was the first time, really, that anyone had made a drama about contemporary political figures. We didn’t know whether people would accept it. But they did–it was hugely popular. And that, on the one hand, gave us huge confidence about going on to ‘The Queen’ and being able to get away with it, and it gave the potential audience in Britain the confidence that it was us doing the film.”

When asked about the difficulty of playing such a well-known figure, Sheen said, “Since I did ‘The Deal,’ I’ve ended up playing a lot of real-life characters, certainly familiar to British audiences. And that’s partly because Peter Morgan has written most of them for me”–including his current part in “Frost/Nixon,” the smash play in which he’s now starring as David Frost in London. “And my process is exactly the same each time. I just completely surround myself with that character. I find all the TV and video footage I can find, all the audio stuff that I can listen to, and I read about them and I constantly have them playing in my head. Not necessarily to try to copy them or mimic them in any way–to begin with it’s just to live with that character for as long as you can, until it just sort of seeps into you. You find yourself imaginatively connecting with the character, so that you start to notice little things they do, little sounds they make. That gives you an ‘in’ to what’s going on inside them. It’s not in any way to try to copy them–you’re looking for something that gives you a little clue to what’s making them tick inside, why they make the choices they make. And then once you’ve built up that inner picture, you start going through the whole process. It becomes less and less a mimicking job and more and more it’s coming from somewhere. And then eventually [in a scene] you’ve got to let that go, because you’ve got to be able to react off each other. So you do all this work beforehand and then let it go and just act.”

Sheen acknowledged that the difficulty of playing Blair in “The Queen” was accentuated in the “public” scenes that would have been most familiar to audiences, in particular the PM’s famous “People’s Princess” speech. “That was my first day’s filming,” he said. “I had to watch that footage over and over and over again–not necessarily to try to do it like Blair did it, although I did try to stay as close to him as possible, but more to make up my own mind about what was going on inside him at that point. Because that speech split people. Some people thought it was one of the great speeches, in that he captured the mood, led the people from the first, gave a voice to the people who couldn’t show how they felt about Diana. Other people felt that it was an absolutely disgraceful piece of opportunistic, ruthless ambition, with completely forced emotion and terrible acting. I had to make a choice–I had to decide, how am I going to do it? So I watched it over and over again to decide whether I thought it was genuine or not. And ultimately I thought that it’s a mixture of the two. It’s a prepared speech–he’s Prime Minister, he knows it’s an important moment, he knows that something’s required of him, so it would of course have to be meticulously worked out. Within that, I think that there’s a lot of genuine emotion.

“In a way that became a key to the whole way of playing Blair. He’s a mixture of things. It was baffling to do that speech first off, because it meant that I was slap-bang in the middle of doing him again, right in the middle of all the ambiguities.”

Sheen said that Mirren, who’s already being mentioned for Oscar consideration, was “a joy to work with,” but he spoke especially enthusiastically about Morgan and Frears. Of the writer, he said, “He seems to be able to deal with important issues and subjects and themes while still making it incredibly accessible and releasing the humor in it. He somehow manages to be very cheeky, he rides a fine line in terms of whether you think people are being laughed at or laughed with.

“The challenge is for the director to be able to match that tone. You could get it terribly wrong. If it topples over too far, you lose credibility, and if you lose credibility, you lose the story. It’s balance, about finding the balance. If you get it right people love all that, because it means you’re not taking yourself too seriously. It allows people in, it makes it accessible and it gives people a laugh. And that’s what Peter does brilliantly. And what’s great about Stephen is that he’s able to harness that, make that work, and not let it get away and not let it get out of control…so that it’s believable, credible, but accessible as well.”

About characterization in particular, he added, “They’re not satisfied with anything less than a rounded human being. So any of the humor in it, and the cheekiness of it, only serves to make you empathize more with the characters. They’re always real human beings–especially about a group of people, specifically the royal family, whom it’s very difficult to see as human. A lot of the time they seem very cold and distant and remote. I think what we’ve managed to do in the film is to humanize them, or at least put them in a context that makes it more understandable why they are the way they are. The humor never serves to belittle anyone, it only serves to make them more human.”

Sheen added that “The Queen” has been embraced by the English public. “I’ve never seen anything like it,” he said. “We thought even if the film was a success, it would divide people because of the subject matter. The British audience and the British critics can be very spiky and very cynical and very hard on you. But they’ve all gotten completely behind the film. I think everyone suddenly felt, this is a film about us, about our country, about our culture, and about a very important moment in our culture. We were all stunned, really, by how across the board everyone seemed to like it and get behind it.”

It’s only one in a recent string of successes for Morgan; “Frost/Nixon” started a bidding war among major Hollywood directors (Ron Howard won), and he also wrote “The Last King of Scotland,” in which Forest Whitaker is earning kudos as Idi Amin. “It’s just an insane period of time for him,” Sheen said. “And I’m just riding on his coattails.”

And though there’s already talk of a third film in which Sheen would play Blair, probably concentrating on his relationships with Bill Clinton and George W. Bush, the actor said of the PM, who recently announced that he’d shortly be stepping down as party leader, “But I’m not riding on his coattails, because I’d be going down the pan!”