There has been much debate about Marilyn Monroe’s vital statistics. She possessed one of the most celebrated bodies in the world and the ludicrous rumours, hyperbole and aura of enigma that surrounded her image were all part of the Marilyn machine. They certainly contributed to the extraordinary level of fame she had acquired by the time she was found naked and dead in bed on August 5, 1962, at just 36 years old.

After all these years, mystery and conspiracy theories still surround her death, but when it comes to her physical attributes, I can put a few facts straight. Contrary to received wisdom, she was not a voluptuous size 16 – quite the opposite. While she was undeniably voluptuous – in possession of an ample bosom and a bottom that would look at home gyrating in a J-Lo video – for most of the early part of her career, she was a size 8 and even in her plumper stages, was no more than a 10. I can tell you this from experience because a few weeks ago, I tried to try on her clothes.

The opportunity arose thanks to David Gainsborough Roberts, a retired investment banker, whose collection of Monroe’s costumes and clothes is currently on display in Jersey. I have always been a massive Marilyn fan. When I was 11 years old, I took full advantage of my parents’ separation by insisting my loving, generous father spend his weekend visits buying me Monroe paraphernalia. By the time their divorce came through, I owned almost every inanimate object in existence – tin cigarette cases, dustbins, badges, postcards, combs, mirrors, books and magazines – anything, as long as it had a reproduction of the screen idol’s face on it. (One year later, much to my long-suffering father’s horror, I did it all over again with Madonna.)

And so, rather egotistically, I’d had visions of myself hamming it up in Monroe’s actual outfits – but in a punky kind of way, a bit like Madonna in Material Girl. I wanted to get to the heart of this enigmatic woman, and I guessed the closest I could get to being in her skin would be being in her second skin.

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One of the first things that struck me about the costumes Monroe wore in her various films is that they were designed with one thing in mind: nudity. Even when they did cover her up – an essential requirement given the studios’ general censorship and the Hays Code (a set of guidelines governing what was “morally acceptable” on screen until 1968) – they were layered with suggestion. It was the costume designer’s task to make the ultimate showcase for that famous body while remaining within the realms of decency.

One of the outfits considered most risqué was a black, heavily beaded, Twenties-inspired dress, by legendary costume designer William Travilla, which she wore in Some Like it Hot. Gainsborough Roberts bought it through Christie’s for $38,500 in 1993 and it got its outing in the latter part of the film in which Sugar, Monroe’s character, sings the beautifully dejected ballad, I’m Through With Love.

Although she eventually won a Golden Globe for Best Actress, Monroe was, famously, a nightmare during the filming of Some Like It Hot. As Billy Wilder rather harshly put it: “We were in mid-flight and there was a nut on the plane.” In 1957, while the film was being shot, Monroe discovered she was pregnant – only to suffer a second miscarriage in 1958 as the film was being completed. Her marriage to the playwright Arthur Miller was breaking down and was eventually to end in divorce three years later, so one can only suppose that Sugar was singing from the heart.

As I tentatively tried to coerce my way into the Some Like It Hot dress, Valerie Nelson, the woman charged with caring for the pieces in the Jersey exhibition, talked me through Monroe’s body shape. Monroe was 5ft 5in (I’m an inch shorter); just over eight stone (I’m ¾ of a stone heavier); she had a respectable BMI of 21 (don’t ask). She had an incredibly narrow back and rib cage but big boobs, so if she were to pop into Rigby & Peller for a bra fitting today she would probably be a 30E.

She didn’t have a long body, and although her legs were a lovely shape (beautiful bony ankles and knees) they weren’t particularly long. She had a very short rise (the distance from waist to crotch), but what made her body so extraordinary was the 13-inch difference between her breast and hip measurements and her waist. In her younger years her vital statistics would have come in at 36 23 35, and although her weight fluctuated throughout her career, she always maintained that out-of-this-world body ratio. A real life Jessica Rabbit.

Nelson tells me that they had to get a special mould made for the corset and swimwear dummies in the exhibition because Monroe was such an extreme hourglass shape that no off-the-peg dummies existed in those measurements. The Some Like It Hot dress just about zips up on me – which is pretty mortifying, considering I had always thought of her Sugar phase as a gloriously plump one.

Not many of the pieces Gainsborough Roberts owns are in good condition (the red show dress from Gentlemen Prefer Blondes bleeds sequins, which have to be painstakingly retrieved by Nelson), but that doesn’t matter a bit to him because, he says, it’s about the stories the clothes tell within their frayed fabrics.

Monroe’s star would have been in full ascension during the filming of Gentlemen Prefer Blondes in 1953. She had just started dating baseball star Joe DiMaggio and had recently appeared on the cover of Life magazine. But although DiMaggio and Monroe cared for each other deeply throughout their lives, their marriage in January 1954 only lasted a disappointing nine months. DiMaggio reportedly found it difficult to reconcile the two Monroes – one, a doting loyal wife; the other, an international movie star and every red-blooded male’s fantasy.

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