Paul Newman: Butch Cassidy and his cancer battle?

When Paul Newman and Robert Redford leapt off that impossible cliff, in the unforgettable scene from Butch Cassidy and the Sundance Kid, fans watching in cinemas in 1969 were rooting for the bandit buddies, hoping they would escape into the sunset, forever free, forever hewn with implausibly good looks. However, the law finally caught up with the nefarious screen pairing. And, off-screen, time eventually would, too.

Redford, the younger by 11 years, is as craggy as he is square-jawed these days and, so far as we know, remains in good health. But not so, it seems, Newman, whose condition has, this week, been the subject of slow but inexorable burn of increasingly doom-laden rumours on the internet and beyond. It can be put no more bluntly put than this: he may be dying of lung cancer.

That unkind vortex of barely-substantiated medical reporting was set off, as it happens, by Martha Stewart, the doyenne of domestic good taste. And she is surely feeling a proper clot. Her latest mis-step is a lesson to everyone who feels the need to write about themselves with a blog or even an occasional Facebook entry. Unintended consequences can follow.

On 6 June, she wrote on her blog about a fundraising event in Greenwich, Connecticut, for the Hole in the Wall Gang, a summer camp in the north-east of the state for children with chronic illnesses that is part of Newman's extended charitable network. She also posted photographs. While Ms Stewart looked hale in a series of happy snaps, Newman, whose acting career is only part of what has made him so precious to America's affections, did not.

There is a glimmer of that Cool Hand-smile that has made women go wobbly for more than five decades but there is no ignoring the shock of his suddenly gaunt visage. Those blue eyes – more celebrated even than Sinatra's – are hidden behind shades that look several sizes too large on a face shrunken by apparent frail health and adorned by a wispy grey beard.

By last night, the rumours were taking on ominous substance. Citing a friend of Newman, the Associated Press issued a snap bulletin with what looked like second-hand confirmation of the worst. The friend said that indeed, the Ohio-born Hollywood icon is battling cancer. He did not say what kind.

That Newman, who turned 83 in January, is not in the best of health has been known to a fairly wide circle of friends for some time. He acknowledged in May 2007 that he was at least slowing down when, in a television interview with ABC, he revealed he was giving up acting for good. "You start to lose your memory, you start to lose your confidence, you start to lose your invention ... I think that's pretty much a closed book for me."

His last contribution to the Hollywood arts was a voiceover for the 2007 Disney-Pixar film, Cars. His were the gravelly tones of Doc Hudson.

As a final role, it was appropriate, of course. Among Newman's many lifelong passions, cars – fast ones – rank among the fiercest. He fell in love with them in his youth, but it was his role in the 1969 film Winning that set him on the circuit in earnest. In 30 years of involvement in the sport, he has driven to second place in the Le Mans race – in 1979 – has tested Indycars in America and remains a co-owner of Newman/Haas Racing, the hugely successful American racing team that lured Nigel Mansell to its stable when he was still king of Formula One.

As we are now learning all over again, Newman has an engaging humility for a man of such iconic status and his self-deprecation extends to any concern we might have about his health. It may also have something to do with good old manliness. Old soldiers don't advertise their wounds.

Fans may recall a newspaper interview he gave four years ago while preparing to drive the Baja 1000 desert race, a gruelling mini Paris-Dakar that takes place annually in Mexico. He was 79 and joked that if his back gave out midway, a quick crunch in the nuts with a hammer wielded by his co-driver would see him right.

Newman has been married for 50 years to the actress Joanne Woodward, his second wife. Never a man to be drawn to the self-indulgent lifestyle of the Hollywood bubble, he has lived with her – his five daughters are long since grown up – in the pleasant climes of Westport, Connecticut, about 50 miles east of New York City. Ms Stewart is a neighbour.

Comfortable in privacy only possible far away from the gossip-mongers of Los Angeles, he helped Ms Woodward run a local theatre, the Westport Country Playhouse, widely respected for its repertoire of solid productions.

And, for the past 20 years, he has – somewhat eccentrically for a worldwide star – overseen Newman's Own, a purveyor of salad dressings and other assorted organic sources. Selling under the motto, "Shameless exploitation for the common good", it exists entirely for the purpose of channelling all and any profits to his Newman's Own Foundation, where the main focus is funding charities for sick children, especially children with cancer.

And all the while – at least until last spring – Newman continued to feed his millions of fans worldwide with film roles. Among his most recent, in 2002, was in The Road to Perdition. His has been a six-decade, 50-film journey that has garnered him no fewer than nine Oscar nominations. He won the best actor award for his role of Fast Eddie Felson in The Color of Money in 1986, a sequel to The Hustler, which confirmed Newman as one of America's most bankable and swoon-inducing stars when it came out in 1961.

Newman, in truth, may not loom so large to those born in the internet generation but any of us with a decent number of miles on our cinema-going clocks can tick off his other great films without pause. Think everything from The Towering Inferno and Cool Hand Luke to The Sting, Cat On A Hot Tin Roof and – of course – the most important buddy movie ever made, Butch Cassidy and The Sundance Kid.

First rumours that Newman might be ailing surfaced last January. It seems clear now that he spent much of the winter fighting an infection, the precise nature of which has never been made public. Forced then to address the speculation, Newman was characteristically off-hand. "I am being treated for athlete's foot and hair loss – unless the doctors know something I don't," he said in the statement and the press left him largely alone.

Then, in May, came two more suggestions of trouble. He withdrew from directing a production of Of Mice and Men due to grace the Westport Playhouse stage this autumn and abruptly cancelled a scheduled appearance on the late night DavidLetterman Show.

Among all the commitments on Newman's plate, showing his support for the Hole in the Wall Camp and all of his charitable endeavours are the most important to him, although he long ago curtailed his personal visits to affiliated camps that have sprung up over the years in places as far afield as Florida, California, Israel and even Botswana. (There are now nine Newman-funded children's camps.)

And so it was that he gamely turned up at the fundraising do in Greenwich last week and, thereafter starred in pictures on Martha's blessed blog. It was some of her own faithful readers who first suggested something may be amiss. "Is Paul well?" one of them asked in a post on the site. "He looks so thin."

The editors of some of America's celebrity magazines – including those for whom providing actual sourced evidence is not always a top priority – noticed too. By early this week, the National Enquirer decided to drop all caution and put the terrible news out there for the rest of us to ponder in dismay: Paul Newman, once a chain smoker, is dying and it's lung cancer. "We have known he is seriously ill for some weeks but his loved ones are being very protective and saying very little," the magazine asserted.

Now, the tragic tidings have started to surface elsewhere. The Los Angeles Times did not include it in its print pages, but chose to report it in one of its web-based Hollywood blogs, aptly named The Dish Rag. "Paul Newman is Reportedly Very Ill with Cancer," it blared. Among the scant details was the news that Newman has been receiving outpatient treatment at the Sloan-Kettering Cancer Centre in Manhattan, one of the world's premier facilities for treating the disease.

Late on Tuesday, an agent for the actor responded to the report. "Not true," Toni Howard baldly informed E! News. But that was not enough to stop the renewed deluge of speculation.

Besieged by inquiries, Newman's spokesperson, Jeff Sanderson, sent a round-robin email to all of America's media outlets with word from the man himself. It said this: "Newman says he's doing nicely". Take from that what you want, but knowing Newman and how little he cares to be fussed over (remember the hammer-to-nuts comment), it was not very reassuring.

And then came the bulletin from the Associated Press. It cited the writer A E Hochtner, confirming that his friend had told him 18 months ago that he was suffering from cancer of some kind. And sadly, Mr Hochtner, who teamed up as a partner in Newman's Own dressing company in the late 1980s, is likely to know. If Newman had hoped to keep his struggle private, the game is up.