Gradually we realise that Duke is Noah, retelling Allie the story of their love every day as she slowly slips away.

As Gosling recalled to Company magazine: “He looked at me and said, ‘I want you to play this role because you’re not like the other young actors out there in Hollywood. You’re not handsome, you’re not cool, you’re just a regular guy who looks a bit nuts.’”

At times, Noah acts a bit nuts, too, exhibiting the obsessive behaviour of an incel. Early on, we see him hanging off a Ferris wheel until Allie agrees to date him, then later, when they part, he writes her a letter every day of the year. But there’s a soulfulness to Gosling’s performance that steers him away from creepy.

Allie’s fighting spirit is much in evidence – especially the scene where she pulls down Noah’s trousers while he’s dangling from the Ferris wheel – but McAdams takes it even further.

When it looks like they might break up, she pushes him hard against his car, furious that he’s taking the coward’s way out.

Throughout the film, there’s a convincing physicality to their love: from the famous kiss in the sea, where Allie wraps her legs around Noah’s chest, to their first attempt at sex, which has them undressing item by item, turn by turn.

Because we don’t see them naked – we just watch them watching each other – what’s clearly erotic for them is sweetly romantic for us.

Cassavetes, Leven and Sparks make much of the natural world. We see the couple surrounded by water – arguing in the rain, rope-swinging into a pool, diving off a boat – a symbol, perhaps, that their love will ebb, flow but ultimately endure.

The flocks of migratory birds we see during crucial scenes remind us how Noah and Allie always come back home to each other.

Off screen, things weren’t quite so rosy, with Gosling and McAdams’ mutual dislike creating an antagonistic atmosphere on set.

While filming a crowd scene, Gosling asked Cassavetes, “‘Would you take her out of here and bring in another actress to read off camera with me?’” the director recalled for VH1.

“He says, ‘I can’t. I can’t do it with her. I’m just not getting anything from this.’”

McAdams was more diplomatic. “We certainly had intense creative conversations,” she told Yahoo Movies UK, 10 years after the fact.

Eventually, Cassavetes staged an intervention.

“We went into a room with a producer, they started screaming and yelling at each other, I walked out,” he said. “I smoked a cigarette and everybody came out like, ‘All right, let’s do this.’ And it got better after that, you know?

“I think Ryan respected her for standing up for her character and Rachel was happy to get that out in the open. The rest of the film wasn’t smooth sailing, but it was smoother sailing.”

The film ends with Noah and Allie dying in each other’s arms, a happy/sad dynamic that proved a winner at the box office, where the film earned US$115 million worldwide.

As well as catapulting the two leads to stardom, it also made them reassess each other’s charms. In a twist straight out of the movies, they went on to become a couple in 2005.

“God bless The Notebook,” Gosling told GQ. “It introduced me to one of the great loves of my life. But people do Rachel and me a disservice by assuming we were anything like the people in that movie. Rachel and my love story is a hell of a lot more romantic than that.”

Perhaps predictably, given their rocketing celebrity, it couldn’t last. When the couple split, in 2007, Gosling complained, “Women are mad at me.

“A girl came up to me on the street, and she almost smacked me. Like, ‘How could you? How could you let a girl like that go?’”

Talk about letting your audience down.