The world exclusive images of the beautiful Some Like It Hot actress and model were sold as original color slides at an auction in Hollywood in November last year from the estate of well known Monroe confidante Frieda Hull.
But the stunning photos went under the radar, selling for a mere $2,240 with wealthy collectors not aware of their true significance.
Now DailyMail.com can reveal the six unique images were the prized possession of Monroe's loyal friend Hull, which she dubbed the ‘pregnant slides’ – a reference to a shocking secret the screen siren kept right up until her death.
The shots were taken on July 8, 1960, outside Fox Studios in New York after Monroe had completed costume and hair tests for her film The Misfits, starring Clark Gable and Montgomery Clift .
The images clearly show a prominent bump from Monroe’s belly which Hull claimed was evidence the star was in the early stages of pregnancy.
And DailyMail.com can reveal the would-be father was not Monroe's then husband, playwright Arthur Miller, it was in fact Italian-French actor Yves Montand – who she met on the set of film Let's Make Love and who she had a very public affair with.
DailyMail.com spoke to Tony Michaels, the man who bought the color slides at the ‘once-in-a-lifetime’ Marilyn Memorabilia Auction held by Julien’s Auctions in LA.
Tony, 56, was a close friend and next door neighbor of Frieda Hull before she passed.
He reveals that Hull had confided in him about Monroe’s secret pregnancy and claims the ‘pregnant slides’ are genuine evidence that she was with child.
The images were the prized possession of Hull, who died in 2014
And in an extraordinary and tragic Hollywood tale Tony says Monroe kept her pregnancy a secret from the world before 'losing' the baby during a hospital visit.
Tony told Daily Mail: ‘Frieda was very proud of those slides and she was very proud to keep them a secret until the day she died.
‘But she told me the story behind them, that Marilyn got pregnant by Yves Montand.
‘It wasn’t a guess or a presumption, it was something she knew for sure, she was very close to Marilyn.
‘As far as she was concerned Marilyn was pregnant in the summer of 1960 and the slides prove it.’
Monroe had wanted a baby more than anything in the world, but that joy was denied her.
She had three miscarriages prior to losing this baby, all of which played out in the public eye. The star suffered with a condition called endometriosis her entire life that caused severe menstrual pain and she also struggled to conceive.
‘I suggested she sell the slides and all her other memorabilia so she could afford a better place to live, but again she refused, she said she would never sell out on her friend of ten years Marilyn...