The spiritual guidance counsellor says she met her spirit fiance in Australia at the start of 2018, but she doesn't know much about him "other than that he feels very ancient, very wise and has been around a long time".
She revealed on the ITV daytime show that after nine months of dating she had been on a tour of Wookey Hole caves in Somerset when he apparently asked her to "hang back" from the group, and then popped the question.
"It was the first time that I ever properly heard his voice, it sounded like it was echoing throughout the whole cave," she said.
"He said "will you marry me?" It's difficult to explain, like it is in my head but then I could hear that as well."
Asked by presenters Rochelle Humes and Phillip Schofield about the wedding plans and why she wasn't wearing a ring, Amethyst explained.
"He's really picky, it's been really difficult," she said.
"We're in the process of planning out the ceremony at the moment."
Amethyst, who believed her ghost fiance was in the TV studios with her, said that she wants to have a family with him in the future admitting she'd "like that", but adding that she doesn't want to "scare him off".
She said that she doesn't have a real name for her partner, but that he appears to her as a ray of light, so a friend dubbed him "Ray".
Phillip tried to ask the spirit a question, with Amethyst translating his answer — that the reason they bonded was through a strong connection.
Amethyst said during a previous appearance on This Morning that she had met the ghost in the Australian bush, and it followed her on to the plane back to England, where they had a sexual experience in the toilets joining the "mile high club".
They are now planning a handfasting, which is a pagan commitment ceremony similar to a wedding.
WHAT THE SCIENTISTS SAY . . .
Christopher French, professor of psychology at Goldsmiths College, University of London, and co-author of Anomalistic Psychology: Exploring Paranormal Belief And Experience says that ghostly experiences are not anything to do with mental illness.
"We need to avoid any kind of simplistic notion that anyone who has weird experiences is suffering from a mental illness.
"What is generally accepted is that hallucinatory experiences are much more common in the non-clinical, totally well-functioning part of the population than was once appreciated. Anyone can have hallucinations — particularly if you are stressed or sleep-deprived."
Professor French believes that most cases of "sex with ghosts" can be explained easily.
"Sleep paralysis is common — 20 to 40 per cent of people say they've experienced it — and is the state between sleep and wakefulness when you realise you can't move. In a smaller percentage of the population, you get associated symptoms that can be very scary. One that's commonly reported is a sense of a presence — something or someone in the room with you.
"You can also get hallucinations where you see dark shadows or monstrous figures, you can get auditory hallucinations — you hear voices, footsteps — and also tactile hallucinations.
"You can feel as if you're being held, you might feel as if someone is breathing on the back of your neck, you can feel as if you're being dragged out of the bed.
"During a normal night's sleep, you go through different stages and it's REM sleep that's associated with vivid dreams."
