Sir Tom Courtenay is 89 years old and telling a story about the day Alec Guinness showed him the script for a peculiar science fiction film he wasn’t quite sure about.

“He seemed uncertain about it,” Courtenay recalls. “But there was something he could smell in it.” The film, of course, was Star Wars. It made Guinness fabulously wealthy.

This is what a conversation with Tom Courtenay is like: an almost offhand tour through the entire span of postwar British cinema and theater, conducted by a man who was present for most of it.

He worked with David Lean on Dr. Zhivago — where he watched Lean hide behind a hotel pillar in Madrid to avoid having to speak to Rod Steiger. He stepped into the role of Billy Liar on stage after Albert Finney originated it, and was compared to Finney relentlessly; then, in 1983, he made a film with Finney that turned them from professional rivals into best friends.

He met Judi Dench at the Old Vic straight out of drama school. He bonded with Guinness on the set of Zhivago and stayed in touch for the rest of Guinness’s life. Queen Elizabeth II told him, at his knighting in 2001, that Manchester audiences might be better than London ones.

The occasion for all of this is The Dresser, Peter Yates’s 1983 film adaptation of Ronald Harwood’s play, which brought Courtenay his only Oscar nomination and which is the subject of this week’s It Happened in Hollywood.

The film casts Courtenay as Norman, the devoted, slightly fey dresser to a declining Shakespearean actor (Finney) touring England during the Blitz. It remains one of the most purely pleasurable two-hander performances in British film history.

Courtenay had done the stage version before the film. He and Finney, who had orbited each other for two decades without becoming friends, discovered on set that the film’s central dynamic — two roles written, as Courtenay puts it, “to make people not friendly” — had the opposite effect.

“We became best friends working on it together,” he says. Finney loved to tease him about his indifference to technical filmmaking. “If there’s a black hole, he’ll find it,” Finney would say, affectionately, about Courtenay wandering into shadows.

The film’s climax — a long, unbroken scene in which Norman falls apart after the actor’s death, finally undone by years of devotion that went unthanked — was shot in a single take at director Peter Yates’s insistence.

“He said, ‘Now go away, lie down, don’t think about it.’ And then they lit it, and I came and did it,” Courtenay recalls. The focus drifts slightly at one point. Yates kept it anyway.

What makes Norman work, Courtenay says, is something quite simple: “He loves the actor more than he loves himself. That’s the key to the part.”

It’s a formulation he returns to when describing his character in his most recent film, Queen at Sea — directed by American filmmaker Lance Hammer and co-starring Juliette Binoche — which premiered at the Berlinale earlier this year and earned Courtenay an acting prize.

In that film, he plays a man fighting to keep his dementia-stricken wife at home against his stepdaughter’s wishes. Two films, four decades apart, animated by the same principle: a love that asks nothing back and gives everything.

Courtenay turned down most of Hollywood when it came calling in the 1960s. He was the face of British New Wave — the Jean-Paul Belmondo of British cinema — and could have parlayed that into something considerably more commercial. He passed.

“I felt the only way I’d develop as an actor would be on the stage,” he says. “I probably overdid it. I overdid my turning things down.” He waited out the production of Dr. Zhivago in a kind of genteel agony, watching Lean search for the right weather and grow his daffodils. He made do with the company: Omar Sharif, Rod Steiger, Alec Guinness.

He has no regrets about any of it, or if he does, he wears them too lightly to notice. At 89, he is still accepting parts he likes, still charming film crews who tease him about his football club, still winning prizes.

Queen at Sea is expected in UK art houses this September, timed for awards season. He doesn’t know yet about a US release.