Sarah Ferguson has confirmed she had a single mastectomy after her sister urged her to go to a routine check.
The Duchess of York confirmed the news on her new podcast, after it emerged she had been diagnosed with breast cancer.
She urged royal fans to go for a screening, and said the disease was found in its early form during a routine mammogram.
Speaking on an episode of her podcast, recorded the day before her operation, she said she was taking the diagnosis as a "real gift to me" and said it would "change my life".
The 63-year-old reportedly left the King Edward VII Hospital in Marylebone, central London, on Sunday, after the operation, and is said to be recovering with family at Windsor.
The Duchess explained: "We're taping the podcast today, but tomorrow I'm going in for a mastectomy, a single mastectomy, it's very important that I speak about it. So when it airs you will know I've been through this.
"I want every single person that is listening to this podcast to go and get checked, to go and get screened."
She also vowed to go out and get "super fit, super well, super strong" and admitted that she only went after her sister insisted.
"Tuesday, two weeks ago, when my sister from Australia, said 'Sarah, get on with it'," she said.
Sarah explained: "I live in the Windsor area, it was a hot day, I didn't feel like going to London, easy to put it off and my sister, who's wonderful and from Australia, I normally do what she says was so cranky.
"She said 'no go, I need you to go'. She was ringing me up about something else ... and getting forceful with me going to see a friend, and I said 'while I'm there I could go and do my mammogram test' to which she even got crankier.
"And she's right. Thank you Jane."
As the public shared messages of support, Sarah shared a new post with her followers thanking them for their kindness.
In the latest episode of her Tea Talks podcast, released today, Fergie revealed that she was due to have a single mastectomy.
She said it was "very important" that she spoke out about it, adding: “I am telling people out there because I want every single person that is listening to this podcast to go and get checked, go and get screened, go do it.
"I’m taking this as a real gift to me to change my life, to nurture myself and stop trying to fix everyone else."
When asked how she was feeling, she admitted she felt some unease, but was coping well.
A spokesman for the Duchess previously told Mirror: "Sarah, Duchess of York was recently diagnosed with an early form of breast cancer detected at a routine mammogram screening.
"She was advised she needed to undergo surgery which has taken place successfully."
The representative added: "The Duchess is receiving the best medical care and her doctors have told her that the prognosis is good. She is now recuperating with her family.
"The Duchess wants to express her immense gratitude to all the medical staff who have supported her in recent days.
"She is also hugely thankful to the staff involved in the mammogram which identified her illness, which was otherwise symptom free, and believes her experience underlines the importance of regular screening."
On the podcast, Sarah opened with a heartbreaking story of how cancer had affected her life and family already.
She revealed that she had volunteered with The Teenage Cancer Trust, around 35 years ago, because her stepdad died of cancer, aged just 50.
Due to this, she decided one of her focuses would be cancer, she said.
Alongside that, her father died of prostate cancer, but Sarah recalled how he went on the radio, "and he said on the radio 'please please please go and get checked, it doesn't matter, go and get checked, it doesn't matter what you're doing, don't think it's not going to happen to you ... go get screened, go get checked, don't wait."
But she said in response: "most of his friends rang him up and said no one wants to hear from you Ronald", drawing a heartbreaking parallel between what her father went through, and what she was.
She added: "I'm so glad dad talked about it."
She also thanked the NHS for her treatment and all the doctors and nurses who helped her throughout.
