The cancer campaigner, blogger, broadcaster and former teacher, Dame Deborah James, has died aged 40.
She had been receiving end-of-life care for bowel cancer at home and had raised millions for cancer research.
The host of the BBC's You, Me and the Big C podcast was given a damehood in May in recognition of her fundraising.
Dame Deborah, a mother of two, was diagnosed with bowel cancer in 2016. Her family described her as "amazing" and an "inspiration".
They announced her death in a post on her Instagram page. "We are deeply saddened to announce the death of Dame Deborah James; the most amazing wife, daughter, sister, mummy," it said.
She passed away peacefully surrounded by her family.
Her family said Dame Deborah shared her experience of cancer to "raise awareness, break down barriers, challenge taboos and change the conversation around cancer".
"Even in her most challenging moments, her determination to raise money and awareness was inspiring."
Deborah James 'taught us how to live and how to die’Tailored cancer care - Dame Deborah's fundraising legacy
Dame Deborah was praised for her no-nonsense approach to talking about cancer, having shared her experiences of treatment and daily life since her diagnosis in 2016.
A deputy head teacher, she started a cancer blog, before writing for the Sun and becoming a BBC broadcaster.
But on 9 May she announced that she was no longer receiving active care and did not know how long she had left.
"My body just can't continue any more," she said in a post on her @bowelbabe Instagram account.
She also launched a new fund, called the Bowelbabe fund, to raise money for research into personalised medicine for cancer patients.
It surpassed £1m in less than 24 hours - smashing her initial goal of £250,000 - and has now raised almost £7m.
Deborah James made a dame by William at her homeDeborah James visits rose named for her at Chelsea
In May, she was given a damehood by Prince William at her parents' home in Woking, Surrey, where she had chosen to stay.
The Duke and Duchess of Cambridge - who donated to the research fund - praised her "tireless efforts" and thanked her for "giving hope" to those living with the disease.
For her part, Dame Deborah said William's visit was "surreal".
"You can imagine the cleaning antics and preparation went off the scale - but it was all irrelevant because William was so kind," she said.