Julia Bradbury has been diagnosed with breast cancer and must undergo an emergency mastectomy.
The 51-year-old TV presenter - best known for hosting Countryfile - has a six centimetre tumour in her left breast, and must also have her lymph node tissue checked to find out if the disease has spread.
Bradbury announced on Instagram: "I’ve been diagnosed with breast cancer in the last few weeks & need urgent surgery.
"I will share what I can with you but I’m sure you understand that I need to focus on my family & treatment, so I won’t be able to respond & engage on here as much as usual."
Bradbury is mother to ten-year-old son Zephyrus and six-year-old twin daughters Xanthe and Zena with her long-term partner Gerard Cunningham.
Bradbury said: "It changes your world forever in an instant. There is no preparing you for those words. You hear 'cancer' and your brain starts to explode."
She added: "Right now I'm simply focused on having surgery because I don't know how I am going to be, if I will have more cancer to deal with, how I will cope with recovery, how life will feel afterwards...
"As it is I am going to lose my breast. I trust that one day I will look down on it and think that was the fight of my life and I have the ultimate battle scar to prove it."
Bradbury went on: "My plan is to come through it and out the other side and I hope to be able to do that bravely enough so that women who are scared to get tested, to get a diagnosis, go ahead. I want to be able to give them a wave and say 'Look, it's horrible, but you can do it too.'"
The tumour was discovered after the TV presenter underwent a routine mammogram in July.
Bradbury was on annual recall for the scan after having found a lump in her breast in March 2020 - which were found to be a cluster of benign cysts.
The TV presenter - an ambassador for Ovarian Cancer Action - discovered the lump while working away in Costa Rica but waited to seek medical help on her return to the UK, because she felt guilty knowing NHS staff were under the strain of battling the coronavirus pandemic.
She said: “I felt a lump and it was sore... but when I got home, it was lockdown and I was distracted with the family and life just took over.”
Earlier this year Bradbury hit back at trolls online after she was body shamed over a selfie she posted on social media - sparking comments that she looked skinny and ill.
Bradbury hit back: “For those of you genuinely concerned: I'm 5ft 9 inches tall (1.75mtrs) & weigh 9 stone 6 lbs.
“According to the NHS BMI indicator my BMI measurement is 19.5. The healthy weight range for my height is between 8st 13lb and 12st 1lb.
“So I'm a healthy weight and 'I should keep up the good work!' according to the website.”
The TV presenter has previously spoken about her struggles to conceives through IVF after undergoing treatment for endometriosis, a condition which affects fertility.
Watch: How to check for signs and symptoms of breast cancer