More than any other star in the notoriously fragile firmament of film, Robert De Niro has seemed indestructible. In the past few years he has successfully reinvented himself

from celluloid psychopath to

comic actor. This week, we learned he was human. He was diagnosed with prostate cancer.

Since it was detected early in

one of his regular check-ups, the famously-fit actor, who turned 60 in August, is expected to make a full recovery. Inevitably, cancer has already affected his life: his father died from it at the age of 71, as did his friend, John Cazale, who starred with him in The Deer Hunter. While we are unlikely to learn how the news affected him, it's a fair bet he will deploy all his energies in fighting the disease in the same way he has worked himself into a physical and mental readiness for acting parts.

De Niro's place in the top three of any poll of best actors appears permanent. His haul of awards includes two Oscars - for best supporting actor as the young Vito Corleone in Godfather II in 1974 and for best actor as the boxer Jake La Motta in Raging Bull in 1980. He also received nominations for best actor in Taxi Driver (1976), The Deer Hunter (1978), and Cape Fear (1991).

We have known him in so many incarnations over the past 30 years that we feel we know how his mind works. That is the ultimate actor's bluff. In June of this year, he received the American Film Institute's lifetime acheivement award, yet even now Robert De Niro is the most secretive of superstars. Public appearances, even non-personal ones such as at the Tribeca film festival he co-founded in Manhattan in the wake of the September 11 attacks, are punctuated by long pauses and few words.

His most memorable roles have been violent ones, his long col-

laboration with Martin Scorsese producing a series of Italian-

American characters operating on the wrong side of the law. It's tempting, therefore, to make the assumption that his childhood must have been a troubled one played out

on the mean streets. The reality is quite different.

The New York into which De Niro was born on August 17, 1943, was a bohemian city of artists and writers. He grew up in a loft apartment in Greenwich Village. His father, Robert Sr, and his mother, Virginia Admiral, were both painters. They divorced - amicably - when he was two. His mother reinvented herself as a successful businesswoman and wrote detective stories, while his father remained a struggling painter.

Young Robert made his schoolboy acting debut at the age of 10 as the Cowardly Lion in The Wizard of Oz. It was the first of many contradictory characters he was to play. The veteran director Elia Kazan, who died earlier this month, summed him up by saying: ''He finds release and fulfilment in becoming other people.''

Famously, De Niro is a method actor, undertaking rigorous research until he feels he has earned the right to play a particular role. In becoming prize-fighter Jake La Motta in Raging Bull, he learned the boxer's art to the point where La Motta himself averred that De Niro could have boxed professionally. In the same role, he put on another 60lbs to show the self-destructive La Motta in decline. Similarly, his saxophone playing in New York New York, in which he was cast as a post-Second World War musician, was said to be of a virtuoso standard. To get the measure of Al Capone in The Untouchables, he supposedly wore silk boxer shorts.

For Taxi Driver, De Niro transformed himself into disturbed Travis Bickle, which included working

for two weeks as a Manhattan cabbie and losing weight. The psychopathic Bickle became his signature role, with the ''You talkin' to me?'' line now one of the most famous in American film.

Raging Bull is regarded as De Niro and Scorsese's collaborative masterpiece. Scorsese had suffered a physical breakdown after New York, New York, but De Niro convinced his friend that Raging Bull could be the cure. Together they reworked an initial adaptation of boxer Jake La Motta's autobiography. Along with his physical dedication, De Niro won over critics with his ability to humanise La Motta without softening him; though some were put off by La Motta's repugnance, none could deny that Scorsese and De Niro had created an extraordinary biopic and Raging Bull received eight Oscar nominations, including Best Picture in 1980.

The early 1980s proved a low point, but, as Al Capone in The Untouchables in 1987, De Niro had his first hit in almost a decade. It was followed by his first comedy success, Midnight Run. Co-starring as a bounty hunter opposite Charles Grodin's bail-jumping accountant, De Niro finally got to show his lighter side, and the hilarious

pair turned Midnight Run into an unexpected hit.

With a renewed enthusiasm for the industry, De Niro founded the Tribeca Film Centre in Manhattan in 1989, home to his own Tribeca Productions plus the independent Miramax. The centre also included a restaurant co-owned by De Niro and decorated with his father's art. It provided a base from which, in his 40s, De Niro launched the most prolific period of his career. He earned an Oscar nomination for his touching performance as a coma patient in Penny Marshall's popular drama, Awakenings, in 1990, but his return to the Scorsese fold, as the duplicitous Irish mobster Jimmy ''The Gent'' opposite Ray Liotta's turncoat Henry Hill in Goodfellas was enthusiastically received by both public and critics.

It was no guarantee of success, with a prolific output after 1990 attracting good and bad reviews in equal number. He turned down the certain winner of a role in Scorsese's blockbuster, Gangs of New York because he did not want to spend the eight weeks required in Rome, but insisted he had no regrets and that he thought Daniel Day-Lewis was ''terrific''.

In fact, he had his own triumph with Analyze This, for which he increased his price tag to $20m and established an entirely new dimension to his acting range - as a comic parody of the obsessive characters for which he is best known. Meet the Parents, in which he played the absurdly stern potential father-in-law, was a runaway success.

His family life has been as complex as some of his characters. He married the actress and singer Diahnne Abbott in 1976. Their son, Raphael, was born in 1978 and he adopted Drena, the daughter of Diahnne's first marriage. They were divorced in 1988. He has twin sons, Aaron and Julian, with Toukie Smith, who were born to a surrogate mother in 1995. In 1997 he married Grace Hightower, with whom he has a son, Elliot. They were divorced in 1999.

Finally, though, real life and professional life have coalesced. The Tribeca Film Center is just a few blocks from Ground Zero and, in the aftermath of the attack, De Niro and his staff were manning food lines for exhausted firefighters. He overturned his reclusive reputation as he narrated the award-winning television documentary 9/11 and the Tribeca film festival became a focus for the revitalisation of the area.

Next year the sequel to one of his biggest commercial successes, Meet The Parents, will be released, although his energies seem to have been more fully engaged by his

new roles as property developer, restaurateur, movie mogul, and

global ambassador for New York. His biographer, John Baxter, argues

that he found anonymity in ''the least likely of all places - the spotlight''. To one who has made that a fine art, prostate cancer is merely another challenge.