When Harrison Ford first told me he wanted to star in a fourth Indiana Jones film, I thought he had taken leave of his senses. He had already inserted an earring in his left ear and started to go clubbing in New York. So, here was a fiftysomething actor with an entrenched image as a straight-talking bloke who appeared to be losing the plot. “Everyone keeps on talking about another Indiana,” he told me. “Steven [Spielberg] has been working on scripts, there is a demand to know what happens to the character, and he’s young enough to have another adventure in him. I am ready. But I am not going ahead with any old rubbish. It will have to be good.”

I left his suite at the Excelsior, Venice, in September 2000, thinking he’d get over it. Once confronted with what faced him in the mirror - a bush of grey hair and creased face - and the aches of limbs bashed around in countless action sequences, he would take time to reflect. But what happened?

He left his second wife, Melissa Mathison, a few weeks later and embarked on what seemed to be a nonstop quest to prove he still had what it takes to once again wear Indiana’s battered hat and wield his bullwhip. All sorts of bizarre stories began to emerge, including old Ford trying to remodel himself with a couple of lap dancers, to whom he had introduced himself as a meatpacker called Tom. He even took up flying, buying himself a plane and visiting clubs in far-flung corners of America, again incognito.

By the time we met up again, he was dating the Ally McBeal actress Calista Flockhart, 22 years his junior, and had convinced himself that Indiana was there for the taking. He had passed his 60th birthday and had made just about his worst film, Hollywood Homicide. “Indiana has moved from a possibility to a probability,” he reported.

Had anyone recognised the time gap, I asked gently. Was there any likelihood his Indiana might appear a tad too . . . mature? “I am not so sure about the ‘mature’ bit,” came the retort. “We want to preserve the physicality of the action.”

Ford was still in his thirties when he first ventured out as Indiana in Raiders of the Lost Ark, and was also in fine shape in Indiana Jones and the Temple of Doom, in 1984. By the time he wrapped on Indiana Jones and the Last Crusade – the hint of it being the final film was in the title - he was 46, but still young-looking enough to have Sean Connery convincingly play his father and not to be embarrassed at appearing alongside a pretty 23-year-old, Alison Doody, as the Aryan seductress Dr Elsa Schneider, while battling Nazis. “We went as far as we could with the character,” he told me in 1990, just a year after the film’s release. “The introduction of Sean was the saving grace. Otherwise, we would have had no place to go.”

So, why attempt to crank the clock back? There are fit-looking men and women in their sixties at every gym, tennis tournament and golf club, but would we want to watch them cavort across the screen for a couple of hours, pretending to be in their prime? Will Ford, I ask, be looking towards special hair tints, make-up and lighting? A few tucks, perhaps? Even Botox? He shot me a look as if he were half thinking of plunging a lethal-looking knife, lying in a fruit bowl, into my heart. “None of that is to my taste,” he said. “I have never been so obsessed with my looks to care all that much. I don’t even bother colouring my hair. I am what I am.”

And so to another meeting with Ford in Los Angeles, just before he began filming as Indiana again. Everything, at last,

was set, including the title, Indiana Jones and the Kingdom of the Crystal Skull. He had been working with Spielberg for months, preparing in utmost secrecy. All cast members had to sign legally binding contracts promising not to utter a word about the script, the story, the stunts and who does what to whom.

Sean Connery, now 77, had already announced he was enjoying retirement too much to reprise Indiana’s father. But there were to be other older actors playing key roles. John Hurt, even older than Ford at 68, would be Abner Ravenwood, father of Marion, Indy’s love interest from Raiders of the Lost Ark, a part to be reprised by Karen Allen, now 56. And Jim Broadbent, 58, would play a Yale professor, with Ray Winstone, 51, as Indiana’s new sidekick, Mac.

“Steven and I have a good idea of what will work and what won’t,” Ford declared. “We know why and how each of the previous films were successful. After all the talk and the plans, it will be good to get going.”

His previous film, Firewall, in which there had been plenty of action, had not enjoyed much success. Critics complained that he was looking a little long in the tooth for throwing himself through windows and beating up his younger co-star, Paul Bettany.

Now, though, he looked invigorated, as if he had lost a decade in the planning process. He was trim, in a dark-blue suit and matching navy polo shirt, and fresh in from one of his many secretive holidays in Britain. He had flown himself in a new jet, with Calista, 43, her adopted son, Liam, 7, and the nanny. They had landed in Wales, via an overnight in Iceland. He had then collected a 60ft narrowboat and navigated canals in Shropshire, pausing at a few pubs along the way. The flying, the landing in Reykjavik - for what he called “the best Indian meal in the world” - and life on the barge all sounded very Indiana.

And so we approach the moment of truth. The film is, supposedly, the hottest ticket of the summer. Its launch at the Cannes film festival a few days before its general release is the movie equivalent of a ticker-tape welcome in New York for a new president of the United States. Harrison Ford will be just 56 days short of his 66th birthday.

We first met on what was my film-set debut, Star Wars, at Elstree, Hertfordshire, in June 1976. He was an unknown 33-year-old and looked, at best, confused. He was playing Han Solo and was clearly unsure of how and why he had come to this. Ford’s previous half-dozen film performances in nine years had produced the one hit, American Graffiti, in 1973. He had just appeared in a television episode of Dynasty – but not the shoulder-padded Dynasty with Joan Collins that later became famous. This was about a pioneer family in the early 19th century. He had, virtually to the moment of his call-up to England, been more successful as a master carpenter in Los Angeles than he had ever been as an actor.

It was an uneasy interview. I was there only because, as a young, inexperienced journalist, I had been foolish enough to accept an invitation to a film that every serious interviewer had ignored.

Ford had been offered as a makeweight for the film’s “real” star, Alec Guinness, who had become so angry with all the script changes that he had pulled out of any publicity.

“I can’t really describe what is happening,” Ford said bluntly. “There are many special effects that are going to be put in later. But I would not have signed up if I did not believe it is going to be a hit.” Neither of us believed a word of it. The set was so ramshackle, it looked as if it had been rejected by the producers of Doctor Who over at the BBC. The few characters who loomed into view, such as Darth Vader, seemed to be dressed in a mixture of black bin liners and spray-on sparkle from a kids’ party.

I thought Ford and his movie were doomed. My judgment was clearly flawed. By the time the film had become the biggest hit of 1977, Ford (who confessed later he thought Star Wars was a big mess) was already reassessing his future. He had set aside his chisel and was now being touted as the lead in a succession of movies.

His interview technique, however, did not improve along with his career. Ford was known, for years, as a crashing bore, always avoided on the television chat-show circuit because he resented giving away anything about himself or his life.

He is currently living in New York, with fiancée Flockhart and family. His divorce from Mathison, to whom he was married for 21 years, which they mostly spent living on an 800-acre ranch in Jackson, Wyoming, went through in 2004. They have a 21-year-old son, Mal-colm and a 16-year-old daughter, Georgia.

Ford’s first marriage, to Mary Marquardt, ended in 1979 after 15 years. They have sons, Ben, 40, and Willard, 38. “I cannot claim to be a perfect father or family man,” he offered.

We have met up regularly for an interview process he does not much like and, bit by bit, personal confessions have emerged. He told me in Paris, launching Patriot Games – the first of his two movies as the CIA agent Jack Ryan – in 1992, about how he kept his socks and suits colour coordinated in his vast wardrobes back at the ranch. His tools were laid out equally immaculately in an expansive workshop. He loved order. He had also not bought a suit for 10 years, taking them all from film sets, where they had been made to measure for his characters. He never asked for an autograph, and his only hero was Abraham Lincoln.

When we saw each other in San Francisco in July 1994, ahead of the release of Clear and Present Danger, the second of his Jack Ryan films, he confessed to never exercising until he was 42. He had been playing tennis for one hour a day, three times a week, and had hired a coach to make sure he never missed.

Ford is also a worrier. “My brain does not relax,” he said. “I am obsessed by details and have to stop myself slipping into obsessive compulsive disorder. It is part of my behaviour, I am afraid.”

A year later, we were at the Essex House Hotel, New York, to talk about the romance Sabrina, a Sydney Pollack film in which he starred opposite the British actress Julia Ormond, who was then considered to be hot stuff in Hollywood. He admitted to being the world’s worst romantic.

“I am just a guy,” he said. “You know how we are.” When pressed, he named Fez, Morocco, as just about the most romantic place on earth. He also never writes a thing - not a diary, a journal or even a note. “I write occasional shopping lists,” he said. “But I am terrified of leaving a record on anything, so I will never, ever write an autobiography.”

I can’t imagine him getting past the first page. Personal detail emerges slowly with Ford, piece by piece, and he looks mighty resentful when revealing anything other than the plot of his latest film. With the latest Indiana, he cannot even do that. And don’t even start on the vanity of an actor who has reached the point of an old-age pension.

Still, he has not come cheaply. There is talk of a record fee of $30m, plus a share of the profits. The script was so slick that certain scenes were executed in a single take. Ford has, apparently, gone back to the future to rediscover his youth and vigour.

“I will never,” he says, with a fervent glint in his eyes, “allow Indiana to become a laughing stock.”

Explore Film

• Film Reviews

• DVD

• Oscars

• Bollywood

Editor's choice

• Burning Bush with W
• Revolution at the new Saatchi Gallery
• Boy George on sex, drugs and Amy Winehouse