Their tumultuous relationship seemed to be headed for a fairytale ending despite a string of wild, headline-grabbing catfights.
But Jocelyn Wildenstein's wedding to longtime beau Lloyd Klein faces its toughest test yet after the fashion designer revealed to DailyMail.com he is battling cancer and was given as little as six months to live.
Klein, 51, had a tumor the size of an orange removed from his armpit and underwent months of grueling chemotherapy after he was diagnosed with lymphoma back in 2013.
Having gone into remission, Klein looked the picture of health when he proposed to Wildenstein, 72, last July, presenting the flamboyant New York socialite with a 32-carat diamond ring 'worth millions'.
But couturier Klein was secretly reeling having been told weeks earlier that the disease was back with a vengeance, spreading to his spine and liver.
Lloyd Klein has revealed to DailyMail.com that he is battling lymphoma again and the disease has spread to his spine and liver. Above he is pictured with fiancee Jocelyn Wildenstein in 2017
The fashion designer had undergone chemotherapy when he was first diagnosed with cancer in 2013 (right) and had been in remission
'It was a catastrophe, the doctors said I could have as little as six months to live unless I responded to a new treatment,' Klein revealed to DailyMail.com.
'I knew at that moment I had to focus on what it is most important in my life - and that's Jocelyn. For me it was so important to recognize that commitment by making her my wife.
'She has always been there for me, throughout our ups and downs. I cannot imagine living a single day of my life without her.'
Wildenstein and Klein's 15-year romance appeared to be over in December 2016 when Jocelyn sank her claws into his face in a now-notorious catfight.
Klein escaped by bundling her into a closet before Wildenstein, famed for her feline features, called the police herself only to be arrested when they saw her partner's wounds.
Klein would face the ignominy of arrest himself just days later when police accused him of pushing Wildenstein when he went back to collect his belongings.
The loved-up pair reconciled when the charges were dropped and said the headline-grabbing tussle only made them realize how much they couldn't bear to be apart.
However, Klein believes the stress of being thrown behind bars and splashed across the papers triggered his devastating relapse.
Klein looked the picture of health when he proposed to Wildenstein, 72, last July presenting the flamboyant New York socialite with a 32-carat diamond ring (pictured) 'worth millions'
Klein, pictured at the hospital, said the news of his cancer pushed him to focus 'on what it is most important' and pop the question
'I think the fights put me under a lot of stress. The scandal hurt me. I started to lose a lot of weight and I knew something was wrong. I was covered in weird bruises,' he told DailyMail.com.
'They did their tests and said it was a disaster. The medication wasn't working. The doctor told me that I may not survive.
'It's not something I like to talk about. I don't like to think of myself as a sick person. So I carried on doing the things I'm passionate about, like my work.
'I also knew it was the perfect moment to propose. It gave me the strength to get better again.'
Doctors at Memorial Sloane Kettering Cancer Center put Klein on a new daily drug regimen and since then his prognosis has improved.
He's launched a new couture line, has worked as a guest designer for a string of top fashion houses and is penning a memoir.
Wildenstein and Klein's 15-year romance appeared to be over in December 2016 when Jocelyn sank her claws into his face in a now-notorious catfight
In a cruel twist, however, Klein's 84-year-old mother Gabrielle D'Allonches is also battling lymphoma in her native France, her chances of a recovery looking less hopeful.
Klein also lost his father Jean Pierre Klein and grandmother Marguerite Klein to cancer.
'It's a terrible, awful thing. And the sort of cancer I have can never be cured,' he explained. 'When the results are very bad you want to kill yourself.
'But it's like living in a concentration camp, you take your pills and somehow you carry on. It's reached my spine and my liver but I don't think about it.
'I'm a fighter. I don't let it scare me anymore. My work is my passion and I have no plans to slow down.'
DailyMail.com revealed in July last year how Klein proposed to Wildenstein at the Versace mansion in Miami, Florida by presenting her with a bespoke, serpent-shaped diamond ring he designed himself.
They would go on to have yet another spat last November when neighbors at Manhattan's Trump World Tower heard screams - however the couple insisted it was nothing more sinister than a bout of noisy lovemaking.
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ShareThe pair liken their ups and downs to the tempestuous romance between Elizabeth Taylor and Richard Burton.
Their wedding is tentatively scheduled for this coming December with the couple hoping to tie the knot in the Château de Vaux-le-Vicomte, a sumptuous baroque castle just outside Paris.
Despite his tragic diagnosis, he has launched a new couture line, has worked as a guest designer for a string of top fashion houses and is penning a memoir
Plastic-surgery loving Wildenstein was the world's most infamous divorcee when they first met, having landed a then-record $2.5 billion settlement in 1999 from her late ex-husband, the art dealer Alec Wildenstein.
In recent years she has not been on speaking terms with their children, Diane and Alec Jnr, after accusing her ex-husband's family of cutting off her multi-million dollar annual maintenance.
Despite owning three adjoining apartments in the Trump World Tower worth close to $12m, Wildenstein claimed in a recent bankruptcy filing that she's been forced to live on $900 a month in Social Security income.
However she extended the pair an olive branch last July when she told DailyMail.com she hoped both Diane and Alec Jnr would attend her nuptials.
The guest list will also include famous names from the world of fashion as well as Klein's 31-year-old son Mathias, who lives in the Swiss town of Basle.
'Our wedding is going ahead as planned,' vowed Klein. 'It's going to be a magical occasion and the cancer is not going to stop me marrying Jocelyn.
'She deserves the fairytale wedding and that's exactly what she's going to get.'
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