Writer Sophie Kinsella, whose effervescent rom-com “Confessions of a Shopaholic” sparked a millions-selling series, died Wednesday, her family said. She was 55 and had been diagnosed with brain cancer.

The family said in a statement on Kinsella’s Instagram account that “she died peacefully, with her final days filled with her true loves: family and music and warmth and Christmas and joy.

“We can’t imagine what life will be like without her radiance and love of life,” the family said.

Kinsella, who also published under her real name, Madeleine Wickham, announced in April 2024 that she had been diagnosed more than a year earlier with glioblastoma, an aggressive form of brain cancer.

“I did not share this before because I wanted to make sure that my children were able to hear and process the news in privacy and adapt to our ’new normal,’” she said at the time.

Kinsella published 10 “Shopaholic” novels starting in 2000 with “The Secret Dreamworld of a Shopaholic,” titled “Confessions of a Shopaholic” in the United States, as well as other fiction. Her books have sold more than 45 million copies worldwide and have been translated into dozens of languages.

Kinsella did not grow up intending to be a writer. One of three girls born to teachers in London, she played piano and violin as a child and also composed music.

While at college, she met musician Henry Wickham and fell in love. The couple had four sons and a daughter.

After graduating, Kinsella began working as a financial journalist and spent her commute reading. The idea to write fiction herself began to take shape on the train, and she worked on her first novel during her lunch hours.

She published her first novel, ”The Tennis Party,” in 1995, as Madeleine Wickham. Soon after, she left her journalism job to focus on writing. Six other books, including “The Gatecrasher” and “Sleeping Arrangements,” followed.

The humorous tone of “Confessions of a Shopaholic” was a change from her earlier books, so she decided to submit it to her publishers under a pen name. Her middle name was Sophie and Kinsella was her mother’s maiden name.

The publishers said yes, and “Shopaholic” was published in 2000 under her pseudonym. The novel, blending humor with a cautionary tale about getting in over your head with debt, was an immediate success.

The first two “Shopaholic” books were adapted into the 2009 film “Confessions of a Shopaholic,” starring Isla Fisher and Hugh Dancy.

In November 2022, after experiencing symptoms including memory loss, headaches and balance troubles, Kinsella was diagnosed with glioblastoma, for which there is no cure. She kept the news private until April 2024. In an interview with TV personality Robin Roberts aired a few months later, Kinsella said she was focused on living in the moment.

“I’ve already lasted more than the average. That’s how we get through. We hope,” she said.

Bill Scott-Kerr, her publisher at Transworld, said Kinsella leaves behind “a unique voice, an unquenchable spirit, a goodness of intent and a body of work that will continue to inspire us to reach higher and be better, just like so many of her characters.”