Easterling and Newton-John had been dating for 16 years and wed for 14, but they'd actually known each other for 20 years before things turned romantic.
The pair had first met at an environmental show, but their bond deepened years later when natural-health businessman Easterling stayed in the guesthouse of Newton-John's Californian home while he was in town for work.
The next day, he was in a car accident en route to the airport and fractured his lower spine, but refused to take painkillers, according to Australian Women's Health.
"I could barely move, so I stayed on (Olivia's) couch until I could travel again," he said.
It was from there that the first blooms of romance began to spark, as they got to know each other even better.
However, Easterling admitted to her that he'd never seen her perform or even watched Grease.
Olivia Newton-John and her husband John Easterling in 2016. Photo / Getty Images
In 2007, he finally made it to one of her shows in Miami, where he lived.
It was that fateful night that sealed the deal – but in a very unexpected way.
"The lights went down and I heard this Peruvian music, and she stepped out and sang Pearls on a Chain," Easterling told The Balancing Act.
"(It's) a very healing song – and that's when I recognised who she was."
However, he didn't mean "recognise" as in her celebrity status – instead, it was her identity as a "healer".
"I thought, 'She's a healer, and this is her medium of healing.' All I could think was that I wanted to introduce her to other healers who work in the Amazon," he said.
Since the '70s, Easterling had been travelling to the region, hunting for "eco-treasure" and earning himself the nickname of "Amazon John", as he told The Balancing Act.
When Newton-John agreed to join him in South America, it confirmed to him that their connection was real.
In June 2008, the smitten couple wed in a private ceremony on a Peruvian mountaintop.
Newton-John later revealed to People: "(It was) just a special sacred site that we went to. We walked there, it was a beautiful day and it was just something we wanted to do."
She also gushed over her new husband to the publication, describing herself as "very lucky".
"I have a wonderful, beautiful husband who is just so loving and fantastic," she said.
"I always tell my friends you're never too old to find love. I found the love of my life at 59 going on 60! I'm grateful."
It was the ultimate fairytale ending, and marked a bright new chapter following a challenging period in Newton-John's personal life.
Olivia Newton-John poses with her then-boyfriend Patrick McDermott in 2001. Photo / Getty Images
A mysterious disappearance
Before her friendship with Easterling turned romantic, the actress and singer had been dealing with the heartache of the baffling disappearance of her ex-partner of nine years.
Ex-cameraman Patrick McDermott vanished during an overnight fishing trip off the coast of California in June 2005, just 30 minutes before his boat was due to return to shore, and with his bill fully paid and belongings stacked neatly on his bed.
At the time of his disappearance, it was claimed that McDermott – who had reportedly filed for bankruptcy and owed US$8000 ($12,750) in backdated child support payments – may have staged his own death to escape his financial woes.
There have been numerous reports of sightings over the years, and in 2017, a photograph reportedly emerged of him in Mexico, more than a decade after he went missing.
In the picture, a man who bears a striking resemblance to McDermott is seen dishevelled and shirtless, lounging next to a mystery woman on a beach.
He was declared dead in 2008, despite not one of the 22 passengers on board his fishing boat having seen him go overboard in San Pedro, California.
Newton-John remained relatively tight-lipped on the situation over the years, although she did admit to Nine's 60 Minutes in 2016 that there were still question marks over his baffling disappearance.
"He was lost at sea, and nobody really knows what happened," she told the programme.
"It's human to wonder. But you know, those are the things in life you have to accept and let go. Because whenever you go through difficult times, there's always those concerns."
In 2009, Newton-John had also described being haunted by the trauma of losing him.
"I think there will always be a question mark … I don't think I will ever really be at peace with it," she told the Australian Women's Weekly magazine.
Flowers adorn Olivia Newton-John's Hollywood Walk of Fame star in Los Angeles. Photo / AP
First marriage
A year before sparking up a relationship with McDermott, Newton-John had announced that she and first husband, Matt Lattanzi, were getting divorced.
The pair had first met on the set of 1980 musical film Xanadu, where Lattanzi, then 20, was hired as a dancer and Newton-John, then 31, was starring as Greek muse Kira.
They married four years later, in December 1984, and welcomed their daughter, Chloe Rose, in January 1986.
In 1992, the couple faced Newton-John's first cancer battle together, with the star's niece Tottie Goldsmith later revealing he was "so supportive" of her.
Just three years later, the couple announced their divorce – but managed to stay friends.
According to People magazine, people close to the pair explained that the difference in their personal beliefs was a large factor.
Goldsmith appeared to confirm that detail in an interview with People in 1995: "The people she chooses to mix with now are very spiritual. She needs to find her equal."
Just over two decades later, as her relationship with the man she later described as "the love of my life" began to bloom, it seems that wish finally came true.
