Best-selling author Colleen Hoover has revealed she has been having treatment after being diagnosed with cancer.

The US writer, 46, known for 'It Ends With Us' and 'Reminders of Him,' said she has nearly finished radiotherapy and that earlier surgery was a success.

She publicly discussed the news in an Instagram post this week, with a selfie showing her in a hospital gown.

In a further message on Tuesday, she told fans: I'm doing much better. My cancer diagnosis was a while ago but I chose to keep it private until after finding out my surgery was successful and what my other treatments would be.

That came after she initially shared the news with fans in a private Facebook chat about a month ago, telling them the cancer had been removed and that I'm okay.

'Huge and scary'

In the Facebook post to Colleen Hoover's CoHorts - her fan group - she explained that she had suffered recurring health issues throughout 2025.

She put her concerns to one side while the film adaptation of 'Reminders of Him' was being shot in Canada, and did not seek medical advice until the movie was finished, she explained.

On her return home, she received her cancer diagnosis.

It felt huge and scary for a bit, and I had to miss out on the 'Regretting You' premiere and some other important career and personal moments, I just wasn't ready to share with anyone until I knew what the outcome would be, she said.

Hoover has not specified what type of cancer she has.

In another Facebook post last week, she said her cancer was possibly linked to environmental and lifestyle factors, such as a lack of exercise, poor diet and stress.

I'm happy and grateful to be alive but I hate vegetables, she said. I hate when I have to get off the couch. I hate sweating. I hate when science is right.

She joked that if anyone saw her at a restaurant eating grilled chicken and drinking water, I'm probably real mad about it.

'I'm a badass'

On Instagram this week, Hoover said the hospital gown selfie was posted to thank Texas Oncology - where she has been receiving treatment - and that she had been open about her diagnosis for a while.

Her latest novel, 'Woman Down' - her first since 2022 - was released this week.

But the author said her cancer update wasn't a ploy to get sympathy-sales for release day.

Hoover, who has three children and lives in Texas, added she had received radiation treatment in Dallas on Monday morning and later surprised fans at a South Carolina bookshop that was hosting a midnight release event for her new novel.

Not because I'm lying about anything, but because I'm a badass, she added.

Her other books include 'It Ends With Us', which has sold more than 20 million copies and was adapted into a film in 2024.