The film was 1993's This Boy's Life. It followed movies such as Night and the City and Guilty By Suspicion in which you'd struggle to argue that the "American Olivier" had telephoned in his involvement: there wasn't even a dial tone. De Niro, the best actor of his generation, appeared to have lost the plot and the Nineties.
Just in time to save the decade, he has noisily returned with a major hit movie, and a minor role in an international high-society call-girl scandal. He was on location, making the high-minded but rip-roaring French Connection-style thriller Ronin, when he was quizzed for nine hours by French detectives investigating a prostitution ring servicing an international cast of celebrity and wealthy clients. The high-cost hookers, often "model/actresses" from Britain and France, were said to charge $7,500 dollars a night. De Niro, 54, who was entirely affable as he talked publicly for the first time since the scandal broke, regards it all as a "non-story". He says he was simply a "minor witness to provide testimony in a case that had nothing to do with me".
But Ronin, which co-stars Britain's Natascha McElhone ("She's going to be a major star," says De Niro) is very much to do with him. He's the boss once again, evoking memories of his power in The Godfather Part II and The Deer Hunter. His friends say the film provided a release for his anger at being drawn into the call-girl scandal.
John Frankenheimer, the veteran director who, like De Niro, has enjoyed fabulous acclaim and endured box office purgatory, was clearly banging the drum for Ronin but nevertheless appeared sincere when he said: "This is the Robert De Niro people have been waiting to see for the last 10 years. He's really a great movie star in this picture. He's the lead and a big hero."
This was not what Frankenheimer was calling the French cops. "They treated him very badly. In reality, all they wanted to do was ask a couple of questions, and they kept him for hours. Bob was horribly inconvenienced. His solution for living at a time like this is in his work."
That work involved filming car chases through Paris at more than 100mph, passing through the same tunnel in which the most famous car crash in history took place. De Niro observed that there was "no thought, no connection" to the death of Diana, Princess of Wales.
"We didn't shoot in the exact spot," he said, "but in other parts of the tunnel. John just wanted to shoot there, and he had planned it before that accident. That tunnel was not particularly that dramatic - it's a small, short tunnel. I always feel one of the last things she must have thought was: `Should I say something?' As for the filming, there was no connection."
It's good to see De Niro carrying a multi-million-dollar movie again, playing a man of decision and action. He's considering playing another man of decision in the remake of Casablanca, though it is, he knows, an enormous challenge to take on the iconic role of Rick created by Humphrey Bogart.
But he's "thinking about it", which is as committed as he gets before he signs on the dotted line.
It's weekend brunch-time in uptown New York and De Niro is dressed for a baseball game. He's wearing jeans, a brown leather jacket and a wary look. He's being asked to ruminate on his career. He is playing nervously with his fingers. Has his career been a struggle over the 25 years since he exploded on to the screen in Scorsese's Mean Streets?
He nods but adds quickly: "Maybe I'm a little looser these days."
He will not, however, give away the secrets of his technical preparation, or comment significantly on how he feels about being considered America's finest living actor.
It's as though he's on some psychological adventure which began to flourish nearly 30 years ago when Shelley Winters cast him in her off-Broadway play One Night Stands of a Noisy Passenger.
The actress recalls seeing him act for the first time: "When he moved across the stage it was like lightning - gave me tingles. Bobby almost never shows emotion in public but years ago here in New York I gave a Thanksgiving party. Bobby was there, waiting for his date, a young actress he had a crush on. She didn't show up until dessert; she sort of floated in. He went into the bedroom and pounded the headboard with his fist. He was crying. He never talked to her again."
If he's mellower these days, he's also busier. We've seen him this year already in the timely and topical Wag the Dog, and as an ageing bull in Tarantino's Jackie Brown. In early 1999 he's in Analyse This, a dark comedy in which he sends himself up as a deranged mobster being cared for by Billy Crystal's hugely and haphazardly neurotic psychiatrist. He has his own film production company and many of the bad movies he's made have arguably been to finance his own film-making, although he will deny this.
"I'd done one side of the camera, and I wanted to try the other side. I never had full responsibility for a film and I wanted that," he says.
De Niro knows he is not infallible. "I like to keep an eye on what's going on," he says, "on what's working and what's not."
And on the subject of the boy wonder Leonardo DiCaprio, he's sullen for a moment. Did he anticipate the DiCaprio phenomenon, even a little, while working on This Boy's Life? He bursts out laughing: "No, no. I didn't. Leonardo? No. He was a good kid. We had a reading just to have a reading. I told the producer: `This kid is very good. We ought to give him a chance.'"
`Ronin' will be on general release from 20 NovemberReuse content