Olivia Newton-John proposed to John Easterling after taking a powerful hallucinogen.
The Grease! star had known her now-husband - who she wed in 2008 - through friends for years before their relationship turned romantic and they had a "hell of a first date" when he invited her to the Amazon.
She recalled to the Daily Mail newspaper: "'He said, 'I'd like to take you to Peru to meet the curandero healers.' It was a hell of a first date!"
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Under John's encouragement, she took "a little cupful" of the plant-based hallucinogen ayahuasca, and though it triggered "room-spinning" hallucinations and nausea, she felt better than ever afterwards.
She said: "My whole body was at peace. I had a feeling of euphoria.
"I'd been taking anti-depressants for six months, but from that day I stopped."
So powerful was the effect, Olivia - who has 33-year-old daughter Chloe with ex-husband Matt Lattanzi - felt moved to pop the question.
She said: "We were sitting by this incredible waterfall. It was magical and I heard myself asking if I could be in his future. We haven't been apart from that moment."
Olivia was diagnosed with breast cancer in 1992 and it returned in 2013, four years before she was discovered to have a secondary tumour in her spine.
The 70-year-old star has turned to cannabis to ease the "excruciating" pain she suffers and admitted she "dreams" of seeing the drug used to treat the "millions" suffering from other ailments.
She said: "Cannabis has now become a big part of my life in a wonderful way. I use it to control the pain in my sacrum.
"John, being a medicine man, grows it for me, and lectures on its benefits. The pain was excruciating when the breast cancer metastasized [spread] to my sacrum.
"It was sleep-depriving, crying-out-loud back pain. I was on morphine, but I weaned myself off it with medicinal cannabis.
"You don't die from taking cannabis, but you do from taking opiates.
"And there are millions of people who could benefit from cannabis: it helps with pain, sleep, anxiety; trauma. My dream is to see everyone benefiting from its healing properties."
This story was originally posted on AsiaOne.com