Observations: Living la dolce vita with Federico Fellini and friends

Ever since Anita Ekberg frolicked under the waters of Rome's Trevi Fountain in La Dolce Vita, the phrase and the city have become synonymous with the film's director, Federico Fellini. One man was lucky enough to experience this "sweet life" with Fellini in the 1950s and early 1960s – William Klein, the American photographer and film-maker. Fresh from acclaim for his unconventional images of the streets of New York, Klein, then 28, had come to Rome from his Paris home to assist Fellini on his earlier film, Nights of Cabiria.

"Fellini was the only game in town," says Klein. "People came to Rome to see two people – the Pope and Fellini." Lack of funding delayed filming, so Klein turned his camera on the city, photographing the people and places from Via Veneto and St Peter's Square to desolate areas ravaged by war. Often he would be in the company of Fellini or others, including Pier Paolo Pasolini or the writer Alberto Moravia. These experiences were vividly captured in his book Rome, which has been re-published to celebrate its 50th anniversary.

Klein remembers the time they were cruising the sidewalks to recruit whores to appear in Nights of Cabiria, and girls would stick their head into their car to say hello to the director. A few years later, while Fellini was posing with a top model on the street by a poster for La Dolce Vita for one of Klein's fashion shoots for American Vogue, passers by would shout, "Hey Federico, what are you doing with that broad?"

Fellini always attracted hangers-on. "He was the ringleader, on to everything, hoodwinking everyone, swinging deals, the Garibaldi of the espressi," Klein says. And there were many girls – which Giulietta Massini, his wife and muse (she starred in Nights of Cabiria), had to live with. They made a strange couple, says Klein: "He was flamboyant. But she was a little bourgeois. She looked more like my aunt Julie than someone who I would have expected him to be with, like Anita Ekberg."

Impromptu visits were often paid to friends such as Vittorio De Sica, the director of Bicycle Thieves, who was on the set next door, shooting a new film. "As a bonus, we found Rossellini. I was a fan of De Sica's and it was the only time I met him. He looked like a playboy. Fellini, on the other hand, looked like a kid on the block – fat, sloppy, one of the boys. Rossellini, already an icon, was like my favourite uncle," recalls Klein.

But life with this crowd would not always be glamorous. "Moravia would take us [Klein and his wife] on a Sunday to these weird family restaurants outside of Rome. There were slippery marble floors, cement walls and 100 families talking all at once with a football match playing on television. It made a tremendous racket and you would have to ask the waiter 20 times before you got served. But Moravia would like to go there to be bored – as it inspired him," he says, laughing.

William Klein: Rome by William Klein is published by Thames & Hudson, £69.95