"As she got more and more worked up, suddenly I found one of her breasts on my plate. I looked up at her, terrified. She barely noticed, regained her composure, and left."
It was a collision of two women whose careers seemed to be heading in different directions.
In 1957, Loren - who this month can be seen in The Life Ahead, her first film in more than a decade - was being feted by Hollywood as the next big thing, an exotic newcomer from a faraway land, Gina Lollobrigida 2.0.
"She sat next to me at the table and started talking - it was like a volcano erupting," Loren recalled in her 2014 memoir. Photo / Getty Images
Mansfield, by contrast, was on her way out. A model and actress who had posed for Playboy and appeared on Broadway, in 1955 she was signed by Warner Bros to be Marilyn Monroe's younger, cheaper and more pliable doppelganger, after Monroe herself grew tired of the bimbo roles.
But Mansfield's success was short-lived; after a series of box office flops, she began to resort to elaborate publicity stunts to keep herself in the headlines. She would arrange multiple product endorsements and photo opportunities each day, and dress in provocative outfits while walking her dogs.
In 1955, she dived into a swimming pool during a press junket in front of hundreds of photographers and "accidentally" lost her top.
After that, she tumbled out of her clothes so often that it's a wonder it wasn't until Janet Jackson's Super Bowl performance in 2004 that the term "wardrobe malfunction" was invented.
In short, Mansfield arrived at Loren's Paramount party determined to be the centre of attention, whether the night was about her or not. It was a star-studded affair, with Gary Cooper, Anthony Perkins and gossip queen Hedda Hopper all in attendance.
Associated Press filmed the build-up: "Shining prominently is Jayne Mansfield." Caught on camera, Mansfield's eyes dart around as she loiters near Loren's table, her chest tilted in a perpetual mid-lean.
In another shot, she can be seen lurking in the background, attempting to navigate her way to the guest of honour. Loren herself recalls Mansfield "swaying on her heels, perhaps not completely sober". There was, she thought "something grand and imperious about each step she took".
When Mansfield eventually sat down next to Loren, the Italian was transfixed: "I saw her and I was going to have a fit because I didn't know what was going to happen. If she moved, everything moved, and it [would have been] a disaster!"
Two years later, another shot of Mansfield spilling out of her dress that night would end up on the cover of Kenneth Anger's notorious Hollywood Babylon, a gossipy exposé of the seedy underbelly of an industry that Mansfield had come to embody.
"Hidden behind Hollywood's enchanted kingdom were some coarse and grotesque sides," Loren would later insist, "which I refused to have anything to do with."
Yet the Italian told Entertainment Weekly in 2014 that her expression in the famous photograph was one of concern, not disdain.
"Look at the picture," she said. "Where are my eyes? I'm staring at her nipples because I am afraid they are about to come on to my plate. In my face you can see the fear. I'm so frightened that everything in her dress is going to blow - BOOM! - and spill all over the table."
A decade later, Mansfield was killed in a car crash at age 34.
For all that the photograph seems to capture Loren and Mansfield at opposite ends of the Hollywood spectrum - the movie star versus the publicity hound; the mysterious European bombshell versus the loud, gauche American sex symbol - the truth is that the actresses had a great deal in common.
Mansfield, a canny operator aware of her own brand, reportedly had an IQ of 149, making her "the smartest dumb blonde in Hollywood".
She moved on to more challenging dramatic roles far quicker than Marilyn Monroe had, and seemed more keenly aware of the absurdities of the Hollywood machine than many of her peers.
"If you're going to be a movie star," she once said, "you should live like one."
Loren's career, meanwhile, drifted closer to Mansfield's, as she became more of a celebrity than an actress. She was never able to make films in America as powerful or stylish as those she made in Italy.
In 1981, she was the first female celebrity to launch her own perfume. Later, she became a regular face around Florida, where she advertised luxury condominiums and spent 17 days in jail for tax evasion (the charges were belatedly dropped in 2013).
She nearly starred as Alexis Carrington in Dynasty (a role that would resurrect Joan Collins' US career), and played both herself and her own mother in a made-for-TV story of her life.
Like Mansfield, Loren was prepared to play the bombshell tongue-in-cheek.
"My aim was to act, to find roles that put me in the category of actresses with a capital A," she told an interviewer in 1991.
"If doing the so-called sexy roles gave me the popularity to choose what I wanted, fine with me. But I always did them with a great sense of humour, pulling my leg, everybody's leg. I had the look in my eye that said I was amused by it all."
