NEW YORK (AP) -- Michael Gambon was in the midst of shooting his fourth film as Professor Albus Dumbledore in the "Harry Potter" films when the series' author, J.K. Rowling, brought forth an unexpected revelation about his character.
The regal Hogwarts headmaster, Rowling said, was gay. When Gambon later saw Rowling on the set of "Harry Potter and the Half-Blood Prince," he had one question: "Is it because of the way I'm playing it?"
While Gambon acknowledges he was "cutting around" on set upon learning the wizard's sexuality, he states clearly: "It doesn't make any difference."
But the 68-year-old actor, who keeps cigarettes hid under Dumbledore's robes, has never shied from a moment of levity. Long known as something of a trickster himself, he hypothesizes that Rowling merely blurted it out to surprise people, and says he identifies with the instinct "to cause trouble or make people think or kick people off their security blanket."
That goes for his acting, too. Gambon revels in doing the "strange, odd and unexpected," particularly on the stage where he's known for altering a performance from night to night.
It's ironic that Gambon one of the most esteemed stage actors of a generation has become most widely identified with a wizard in a series meant for teenagers, not unlike Ian McKellen's experience playing Gandalf in "The Lord of the Rings."
Now, Gambon says, it's common for a young child to anxiously spy him while sipping coffee at a cafe.
"It's very odd," Gambon said in an interview shortly after the film's crazed London premiere. "I hadn't realized before just how powerful these things are. I just do the job and go home and you forget it" adding a snap of his finger.
Gambon inherited the role after Richard Harris, who played Dumbledore in the first two films, died in 2002. He has company in the cast, divided between young upstarts and elder statesmen of British acting: Alan Rickman, Jim Broadbent, Maggie Smith.
"They rang me up and said, `Will you do it?' Like any other job I said, `Sure,'" recalled Gambon. "Then you find yourself in the middle of this thing."
Gambon comes from a different generation of actors: a "working actor" eager for constant work and not as "fussy" as today's younger crop of thespians. Born in Ireland and raised in London, Gambon was classically trained and eventually recruited by Laurence Olivier for his National Theatre Company.
He established himself on the stage with widely hailed performances of Shakespeare ("Othello," "Macbeth," "King Lear") and Harold Pinter ("Betrayal," "The Caretaker"). He was given the nickname "The Great Gambon," praised for the physicality, nuance and unpredictability of his performances.
"I've played quite a lot of crooks and killers, and that's quite interesting," says Gambon. "Then Dumbledore is the complete opposite, isn't he? He's a nice old man."
He's amassed more than 100 film and TV credits in his career, predominantly as a character actor. Roles of note include Philip Marlow in the mid-`80s BBC series "The Singing Detective" and Fyodor Dostoyevsky in 1997's "The Gambler." Others include Robert Altman's "Gosford Park," Wes Anderson's "The Life Aquatic with Steve Zissou" and Michael Mann's "The Insider."
Gambon will appear in the final two Potter films, which are being shot and will be released in fall 2010 and summer 2011, respectively. But fans of Rowling's books know well that "The Half-Blood Prince" is a film of particular importance to Dumbledore and Gambon for reasons that set off shrill sirens of "spoiler alert."
Suffice it to say, "The Half-Blood Prince" represents a culmination of Gambon's time in Potterville an era he views with warmth.
"This will stick out as being a happy memory, being with a thing for so long and the worldwide love of it," says Gambon. "You never forget that."