He That Plays the King.(Sir Ian McKellen)

Strolling through Limehouse, in London's East End, you pass streets, like Shoulder of Mutton Alley, that still give off a whiff of Elizabethan hurly-burly, and ancient pubs like the Grapes, which has been serving ale from the same spot since 1583. Soon you come to Sir Ian McKellen's narrow five-story house, which was built in 1733. McKellen had the place renovated in 2000, while he was away in New Zealand being Gandalf the Grey, the hoary-haired wizard in "The Lord of the Rings: The Fellowship of the Ring," which grossed nearly a billion dollars worldwide and made McKellen, in his sixties, an international star. At the far end of the house's paintings-crammed ground floor, beyond McKellen's writing desk, is a dormer window, and beyond the window, no more than twenty feet away, the murky Thames rolls by, carrying the dust of ages.

McKellen is also a conduit of history. Since his first professional performance, in the Belgrade Theatre Company's 1961 production of "A Man for All Seasons," in Coventry, he reckons that he has "never been out of work." His adult life has been spent between the rehearsal room, the stage, and the movie set. One of the era's great classical actors, he has played most of Shakespeare's major heroes and villains, including Macbeth, Iago, Richard II, and Richard III (in a stellar modern-dress interpretation that he reprised for the 1995 film, directed by Richard Loncraine). Last January, McKellen began rehearsals for a season in the Royal Shakespeare Company's productions of "King Lear" and Chekhov's "The Seagull." (Both plays, directed by Sir Trevor Nunn, will be at the Brooklyn Academy of Music in September.) This is the third "King Lear" in which McKellen has featured--he was Edgar in the 1974 Actors' Company production, which also played at BAM, and the Earl of Kent in a 1990 production--but, at sixty-eight, he is attempting the part of Lear for the first time. The R.S.C. tour is a test of McKellen's redoubtable stamina: he performs Lear four times a week and Chekhov's Soren twice. Playing Lear, he told me, is "the most difficult thing I've ever done."

McKellen has grown up and grown old with the British public, which accounts for some of the intensity of his relationship with his audience. He sees the enterprise of acting as a kind of service industry, and the fact that a large portion of the stories through which he has won renown are Shakespeare's gives the task, for him, a certain moral purpose. "I'm not just doing it to satisfy myself," he said. "I'm doing it because I know that, if the audience only gets this story and the way that it is written, their lives are going to be changed. That's the preacher in me." He added, "I'm very sentimental about Stratford. I die as King Lear a hundred yards from where Shakespeare died, a hundred yards from where he's buried. It's very moving that he was an actor. It all happened because, like me, he'd seen actors at work when he was a kid. He's one of us. So there's a sort of responsibility to do your very best by him."

Over the years, McKellen has reached out as happily to the hoi polloi as to the highbrows. In 2006, playing the leering Widow Twankey in a pantomime version of "Aladdin" at London's Old Vic, he tapped into his music-hall roots and discovered his inner Dame, a lewd, garish old tart who, according to his Cambridge contemporary the director Stephen Frears, echoed "all the Northern comics he would have seen--Norman Evans, Frank Randle, and Les Dawson." McKellen's democratic appetite for performance has also extended to guest appearances on the venerable North Country soap opera "Coronation Street," "Extras," "The Simpsons," and "Saturday Night Live," which he hosted in 2002, as well as appearances in the movie "The Da Vinci Code" and the "X-Men" and "Lord of the Rings" trilogies. In 1994, McKellen, who calls himself a "front man" for gay activism in Britain, took the pitcher's mound at Yankee Stadium before a crowd of fifty thousand to close the Gay Games. "Good evening, I'm Sir Ian McKellen," he said. "But you can call me Serena."

In person, there is nothing camp or frivolous about McKellen. On the overcast May morning when we first met, his ease and accessibility were reflected in his dress--a blue T-shirt, jeans, and low-top green sneakers. McKellen has a large head, made even larger these days by the unruly mass of white hair and beard he has grown for the role of Lear. His face is a craggy terrain, and the bags under his heavy-lidded eyes have deepened and drooped. But, if McKellen's face carries the striations of time, his body doesn't. He is tall and supple, with a dancer's form that he enjoys showing off. (He has stripped onstage for "Coriolanus" and stepped out of a shower in a TV documentary; in the storm scene of "King Lear," he stands truly naked against the elements.) When he talks, he has a tendency to act out his anecdotes. Leaning on the black marble counter of his mauve kitchen, he said, "Every night when I lift Cordelia--she stands on a chair and I lift her in the wings--I think, Ow! Ian, you should have gone and done some more exercises." He suddenly tottered toward me with the imaginary princess in his arms. "The role isn't as tiring as I thought," he added. "Perhaps because it's often played by men who are older. At the end of 'Hamlet' you've got a fight. At the end of 'Macbeth' you've got a fight. At the beginning of 'Coriolanus' you have a fight. You're forever running here, there, and everywhere. Lear doesn't run. He's a talker. Where it's wearing on you is emotionally and mentally. I do feel I've had that sort of workout by the end of the evening."

McKellen walked out onto his patio overlooking the Thames. Greenwich was upriver to the left, and just visible on the right were the peaked roofs of Tower Bridge. To mark the beginning of the new millennium, McKellen threw a sit-down dinner for forty on New Year's Eve, 1999. "One of the entertainments for the evening was going to be watching the Queen going upriver to the Millennium Dome," he recalled. "A really unattractive boat came chugging up the river. She was on City Cruises! If she hadn't been wearing lime green, one wouldn't have noticed. We wanted proper people rowing her up. . . . I wanted her to do the job superbly."

As a master of theatrical ceremony, McKellen has given a lot of thought to the notion of royal ritual and performance. "Your kingship is created entirely by the way other people react to you," he said. His Lear enters the stage to a show of worship that contains a warning: nobody is to approach. Still, because his authority is absolute, he speaks softly at first; he doesn't need to raise his voice. "He holds all the cards," McKellen said. He added, "Having seen power people at close quarters, functioning, is essential if you are going to be convincing." (At a dance at Buckingham Palace recently, McKellen and his friend Dame Judi Dench--they were ...