Kerri-Anne and John met in New York in the late 1970s, following KAK's abusive first marriage to music producer Jimmy Miller.
Kerri-Anne sought support from friend John Kennerley, who helped her leave the marriage.
'When she arrived at my doorstep with a black eye and a bit of a bloody nose, I realised exactly what was happening,' John previously recalled.
The pair returned to Australia and were married in 1984, in a glitzy ceremony in 1984 at the Sydney Opera House.
The couple shared two stepchildren and lived in the Sydney suburb of Woollahra, along with their beloved pet golden retriever, Digger.
The couple had one of the most admired relationships in showbiz and would often host parties where John - a model-train enthusiast - would treat visitors to guided tours of his model railways, which featured heavily in their 1870 home.
“After school I’d lean over the bridge to watch the trains and I’d come home and my white school shirt would be covered in soot,” John - a retired UK pools executive who founded NSW Lotto - previously told the Sydney Morning Herald.
The pair lived the high-life, skiing in Aspen each year; exotic holidays on safari in Africa and cruising around Europe.
In 2009, the loved up pair flew to Port Douglas in 2009 to renew their wedding vows.
The longstanding couple also faced incredible lows. In 1998, John battled bowel cancer and in 2012 Kerri-Anne beat breast cancer.
In 2016, John suffered a horrific fall at a golf resort near Coffs Harbour, leaving him paralysed.
Kerri told Sunday Night that following the accident, “My life as I knew it is over”.
“[He] lost his balance and fell backwards. Spearheaded the ground,” she told reporter Mike Willesee.
“And as soon as I went round ... went round a few steps down, and he was then on his side. All he could say is, ‘I can’t feel anything’.
“And we were then waiting for the ambulance. I just sat at his head and said everything was going to be OK. Nobody wanted to roll him.”
Meanwhile John had nothing but praise for his wife.
"[Kerri-Anne] is very loving and she has been the strength of my whole recovery," John explained late last year.
"Without her I don't think I would have attempted it but, as I say, she was there when I woke up and she has been with me every day."
He added: "It is really, really been hard... I have appreciated it, she never faltered. Never faltered."
John is survived by wife Kerri-Anne and his two kids from a previous relationship.