Colin Firth’s royal pains

Reporting from New York — Colin Firth, playing a monarch with a debilitating stutter in “The King’s Speech,” found something unusual happening during shooting: He began experiencing symptoms in parts of his body not associated with speaking.

“At the end of some days on set I would get headaches, and a few times I did something weird to the nerves in my left arm and couldn’t move it. I still don’t know what it was,” Firth said of his leading part in the highly anticipated royals drama, which opens in Los Angeles on Friday. “It sounds like an actor trying to talk about the rigors of the role, but it really was the strangest thing.”

Filmgoers might not be surprised to hear that Firth’s performance took on a physical cast. In a turn as demanding as it is subtle, the actor plays Bertie, the future King George VI, afflicted by a stammer so crippling he can’t speak publicly. It’s a malady with geopolitical consequences, as he is urgently needed to reassure a British public anxious about Hitler’s rise and Nazi aggression. But the stuttering also has an emotional aspect — Bertie is the product of a repressed upbringing and a friendless adulthood.

Director Tom Hooper’s film traces an improbable real-life relationship that develops between Bertie and a quirky Australian speech therapist ( Geoffrey Rush). “The conceit of the film is to take a man and isolate him as much as you can possibly imagine — and then set up a situation where a friendship has to be achieved in spite of that,” Firth explained.

Even months after it finished shooting, the movie continues to play havoc with Firth’s well-being. Stepping into a SoHo restaurant the day after getting off a flight from London, the actor shakes his head and, with characteristic drollness, says, “I’m too old for time zones.”

He should be used to traveling. The British actor finds himself hopping planes and oceans promoting an acclaimed awards-season role for a second straight year.

Best known in this country for romantic comedies such as “Bridget Jones’s Diary” and “Love Actually” (and, to a devoted female audience, Mr. Darcy in a 1995 British television adaptation of “Pride and Prejudice”), the 50-year-old has recently found himself on a new acting level. Last year, Firth’s performance as a grieving gay professor in “A Single Man” earned him a lead actor Oscar nomination. He’s all but assured of repeating the feat with “The King’s Speech.”

Firth finds the sudden attention a little surprising. “Someone asked me this morning [about my acting]: ‘Did you get better?’” he recalls with a slight laugh. “I’ve just carried on doing what it says in the manual.”

Of course there’s no blueprint for becoming a successful leading man, and even if there was, Firth has hardly followed it. The actor had always sought serious roles but has often ended up as the guy chasing the girl in romantic comedies.

“I’m more comfortable in dramas than in comedies, and I think there’s a certain irony that for so many years I was involved on the comedy side,” Firth said, his easy eloquence, wavy auburn hair and fashionable plastic glasses confirming his reputation as the thinking-woman’s heartthrob. “Some of them I’m really happy to have done. But they’re not necessarily movies that I would go to.”

Although his new role never devolves into bathos, Firth’s Bertie doesn’t shy from the more brutal manifestations of his disability. “Tom pushed me not to be afraid of how much stammering we were going to listen to,” Firth said, his voice occasionally veering into a nasal register that is used to such stark effect in the film. “There would be days when I’d say, ‘You want that much, you really want me to do that?’ And he’d say, ‘We have to go a darker place.’”

Hooper, for his part, says “Colin was concerned there would be too much stuttering and the audience would find it unwatchable. My feeling was [Bertie’s condition] had to be profound.”

Hooper says that Firth was the rare actor who could pull off the tricky feat of imbuing a remote monarch with heart. “One of Colin’s great gifts as an actor is that he’s nice to the core of his being, and you can see his tremendous humanity even as he’s playing someone who’s not emotionally available,” Hooper said.

Firth also pored over hours of audio recordings and photographs of King George VI to prepare to play the historical figure. Yet the result is hardly a starchy period piece but an inspiring and often quite comic crowd-pleaser; the movie has played extremely well at the Telluride, AFI and Toronto film festivals, the last of which gave the film its top audience award.

“The emotional response we’re getting even from people who couldn’t care less about history or English people is almost inexplicable,” Firth said. “The only way you can even try to explain it is that the friendship and isolation and parental-heartbreak aspects chime all the way through the story.” (Rush has a simpler explanation: “I think that the Americans might connect just on the level of therapy,” he quipped at a recent Los Angeles screening. The actor later told The Times that “it was exquisite to watch someone go so deep inside a character in a scene and then, when the camera shut off, be able to stand back and objectify and analyze that character.”)

Of course, there’s also the fact that royals continue to fascinate the public on both sides of the Atlantic.

Just a week before the movie’s U.S. release, the point was proved again with news of the engagement of Prince William, who happens to be Bertie’s great-grandson.

Firth said he actually had little interest in the British monarchy — “the first book I read about the royals was for this movie” — and for years has mostly been fascinated primarily by rock stars.

The actor, who had a peripatetic childhood in England, Nigeria and the U.S., said it became clear to him as he shot this film how unappealing a royal’s life could be.

“This movie debunks the idea of a privileged upbringing,” Firth said. “I wouldn’t change places with that guy no matter how many countries are in my empire.”

steve.zeitchik@latimes.com