Star of Pollyanna and The Parent Trap, and the daughter of the late actor John Mills, Hayley said that she was given the diagnosis in 2008, on her birthday, April 18th.
Hayley wanted to open up about her experience, following her recovery. When Hayley Mills was diagnosed with double breast cancer she was determined to beat it and signed up for chemotherapy.
But the side-effects were horrible. After just three sessions, Hayley decided to quit the treatment altogether and try something else.
It was only earlier this year the Wild At Heart and The Parent Trap star revealed her cancer battle, which began in 2008.
Now, four years on from that traumatic time, she explains how, despite turning down chemo, she is happy, healthy and cancer-free.
"It made me feel awful," she sighs. "I was more frightened of the chemo than the cancer.
"I could feel it draining me and killing me. I felt I was dying."
Hayley, who turned 69 in 2015, puts her survival down to the alternative treatments she tried out to beat the disease into remission.
She is careful to stress her decisions were personal and that what worked for her might not suit all cancer patients.
But she clearly has sympathy with Sally Roberts, the mother who made headlines in the run up to Christmas with her court fight to stop her seven-year-old son Neon's treatment – because of possible side-effects such as infertility or reduced IQ.
After having surgery, Hayley says that she just could not face going on with her chemotherapy regime.
"I thought how can I fight something if I feel so ghastly?
"I want to be able to take charge and be involved in this battle. It was about the quality of my life."
The actress, who found fame aged 13 in 1960 movie Pollyanna, believes there are always choices.
She says: "I always say a tremendous amount of healing is in your own hands.
"What you can do to boost your immune system, and what you can do to keep your mind, body and soul healthy and positive is important."
As a starting point she changed her diet, cutting foods that might "feed cancer" including sugar, dairy and acid-creating foods.
Then she embarked on a serious course of exercise and meditation.
But, as Sally Roberts found, the medical profession offers little support for alternatives.
Hayley says: "It's a big decision. Most other routes are not endorsed – they offer surgery and chemo and radiotherapy and that's it.
"When you step off that, you're on your own because all those other things, they'd just say were a waste of time.
"So you have to decide what route you're going to take and be prepared to find something you can believe in 100%.
"If that's chemotherapy, do it, and don't be afraid. Be supportive mentally. Visualise things going in there and killing off all the little f***ers.
"I started with chemo and then stopped. I didn't do the radiotherapy.
"And I'm not saying it is what everyone should do, all I know is that's what felt right for me.
"There are some fantastic, brilliant alternative doctors out there.
"It doesn't make sense that there is only one way of dealing with cancer."