Within a few short years of that meeting, Clark's own brand of decadence had helped mould an entire generation.
His clothes were worn by Mick Jagger, Twiggy, Marc Bolan and Jimi Hendrix, his name was synonymous with the Swinging Sixties and his portrait - with his wife, Celia Birtwell, and his cat, Percy - painted by David Hockney, was hanging in the Tate Gallery.
One can only wonder, then, what the late Jarman would have made of the fashion designer's spectacular descent into hardship and obscurity three decades later, of his erratic life in a west London council flat and of his pleas for mercy after being convicted of assaulting a police officer.
Yesterday, as the world of fashion and its followers mourned his passing, remembering the golden years at Clark's boutique, Quorum, on the King's Road in Chelsea, the questions seemed difficult to answer.
In the intervening years, Clark, 54, had become bankrupt, had split from Ms Birtwell, his emotional and business partner until 1974, and had begun a gay relationship.
Kenneth Sneddon, 35, a neighbour in Penzance Street, Notting Hill, said Clark would become deflated when his career was discussed.
"I never spoke to him about his famous past," he said. "Whenever it was mentioned, he would become all reflective.
"His flat was organised chaos and artistically neglected. He liked smoking brightly coloured cocktail cigarettes. He would smoke them when he could afford them, and when he couldn't afford them he would just smoke any old cigarette."
Other neighbours described Clark as dressing like an ageing hippie and said their children would tease him about being gay, provoking him into chasing them in a good-natured manner. Like most of Clark's clients, Mick Jagger yesterday found his death hard to take. He recalled a "flowery zip-up jump suit" designed by Clark for the Rolling Stones' 1972 Exile on Mainstreet tour. "Ossie was a great friend, and a wonderfully talented clothes designer," he said.
Ms Birtwell, mother of Clark's sons, Albert, 26, and George, 24, spoke of his "unique talent" and the good years they spent together.
"The years 1966 to 1974 were great years," she said. "He had the marvellous ability to produce these marvellous chiffon silks and snakeskin clothes, which everybody of my generation loved.
"He was a real star, but unfortunately it didn't last. I think he got broken by it all."
In February of this year Clark reached rock bottom, appearing at Southwark Crown Court on charges of assaulting a policeman after crashing into an unmarked police car, apparently while drunk.
He was convicted, but escaped prison "by the skin of my teeth", as he put it, after desperate pleas in mitigation by his counsel, Oscar del Fabro. "He was a famous designer in the Sixties," recalled Mr del Fabro. "He was the progenitor and founder of an industry that is worth many millions of pounds. His contemporaries have gone on to greater things, but he has fallen on hard times. You can see the tragedy of a reputation and empire which has fallen by the way."
So, what did happen to Ossie Clark? The answer may be found in a "correspondents' questions" page of the Daily Mail in April 1994 when, above a question on the origins of the expression "choc-a-block", a reader asked, "Whatever happened to Ossie Clark?"
Replying personally, Clark wrote: "After the excitement of the Sixties and Seventies, travelling the world, having my picture in the Tate Gallery, etc., things calmed down. By 1983 I was in financial difficulties and had divorced.
"Around this period I lost my love of the fashion world and restricted myself to designing three or four ball gowns or wedding dresses a year for friends. I also took up new interests - writing, drawing, music, walking and spending time with friends. My previous somewhat unreal lifestyle came to an end as I sought more genuine values.
"I had the same ups and downs most people have, but I enjoyed the next 10 years and felt privileged at being my own master. I feel this is the most important thing for a creative mind, even if it causes financial hardship.
"I've decided I'm ready to return to designing. I've had discussions about setting up my own studio, and I'm waiting for offers from potential patrons. Until then, I am enjoying producing exclusive one-offs for special customers."
And, according to neighbours, Bianca Jagger had recently called round at the flat for a fitting.
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