It was slinky, sexy and traffic-stopping – and one of Nadia Bartel's most prized possessions - so it didn't take the glamorous WAG long to realise it was missing when she was rearranging clothes in her lavish dressing room.
"The dress disappeared when Nadia wasn't around and it didn't take her long to realise that someone Jimmy had entertained at their home had 'borrowed' it," reveals one of her close mates.
"It's not the sort of dress you misplace, and they had a huge argument over it. Let's put it this way, Nadia didn't for a second think that one of Jimmy's AFL buddies borrowed it. She realised it had to be a woman."
Another source says the dress was only returned after Jimmy rang the woman in question and demanded she return the dress ASAP.
"She was in a hairdressing salon in Geelong at the time and he absolutely tore shreds off her," our source says.
The woman in question was not Lauren Mand – the blonde bombshell model who has been named at the centre of the Bartels' shocking marriage split – but a woman Jimmy knew from Geelong, where he and Nadia lived until he retired in 2016.
"He was screaming down the phone at her, demanding she return the dress," the source says.
Friends say the missing dress and the realisation that Jimmy, 35, had been entertaining a woman in their $3 million Middle Park mansion while Nadia was away with their two young children, was "one of the catalysts" for the split.
It's unclear exactly when the dress went missing, but friends say the marriage was already on the rocks in April when Nadia went to California with fellow WAGs Rebecca Judd, Jessie Murphy and Kylie Brown to soak up the sunshine and music at the Coachella music festival.
"When Nadia went to Coachella, it was the beginning of the end," confirms our source. "Jimmy was getting increasingly upset at what he saw as Nadia's total lack of respect for money, and they argued over the bills that came pouring in from that trip. He read the riot act to Nadia over her spending.
"She'd started her own business and he'd tipped a lot of money into it. He told her she shouldn't be acting like a rock star when she had a business to run. Jimmy came from a pretty poor background and he's careful with his money."
Nadia, 34, who now has almost 550,000 Instagram followers, launched e-store The Con-Nection with her sister Michelle Coppolino in mid-2016 on the back of the success of her online fashion hub, Chronicles of Nadia.
The Bartels' split first came to public attention a few weeks ago when fans noticed that both Nadia and Jimmy had unfollowed each other on Instagram, but friends say they separated in June when Nadia moved out of their marital home and into her parents' home.
Within days of unfollowing each other, retired Geelong Cats star Jimmy was linked to model Lauren Mand, and it soon emerged he had spent time with her in July when he went on a solo trip to London, where Lauren had moved to in March.
WATCH: Nadia Bartel is set to get nude in The Real Full Monty: Ladies' Night on Channel Seven. Story continues below...
Nadia, who shares three-year-old Aston and 10-month old Henley with Jimmy, is understood to have found out about the affair though a text message, and is rumoured to be preparing to do a tell-all about the breakdown of their five-year marriage.
"Although I'm heartbroken, I don't want to comment specifically on what's been reported about Jim's trip to the UK as I don't think that is in anyone's interests," Nadia told the Herald Sun newspaper in her only official comment on the split.
"My single focus now is to continue to protect, care and provide for my two beautiful boys as this is a personal matter."
Nadia, who will star in The Real Full Monty: Ladies' Night on Seven later this month, met Brownlow Medal-winning Jimmy when she was working as a promotional model at Melbourne's F1 Grand Prix in 2008. They tied the knot in a lavish wedding on the Bellarine Peninsula six years later.
She's been described as a Melbourne socialite and has been seen and snapped at dozens of fashion and celeb events in the past few years, but little else is known about the blonde bombshell.
She relocated to London in March but was back in Australia last week. According to insiders, Lauren has been calling Jimmy her "boyfriend" for months, and has long aspired to become a more prominent socialite. She was spotted having beers and lunch with Jimmy recently at the Manly Greenhouse restaurant in Sydney. The former AFL star confirmed he had split from Nadia when he returned to his commentating role on 3AW in mid-August.