Sophie Kinsella, the bestselling author of the “Shopaholic” series of novels, has died, her family announced Wednesday, 18 months after she revealed she had an aggressive form of brain cancer.

She was 55.

Kinsella enjoyed extraordinary success, selling more than 50 million copies of her books in 60 countries, with translations into more than 40 languages.

“We are heartbroken to announce the passing this morning of our beloved Sophie (aka Maddy, aka Mummy),” a post on her official Instagram account said on Wednesday.

The post added that Kinsella died peacefully, surrounded by her “true loves: family, music, warmth, Christmas, and joy.”

The statement continued: “Despite her illness, which she bore with unimaginable courage, Sophie counted herself truly blessed — to have such wonderful family and friends, and to have had the extraordinary success of her writing career.”

The English writer first found fame with “The Secret Dreamworld of a Shopaholic,” also known as “Confessions of a Shopaholic,” published in 2000, following the exploits of journalist Becky Bloomwood, who loved shopping but was terrible with money.

Isla Fisher starred in a big-screen adaptation of “Confessions” in 2009, made by Disney.

But Kinsella’s first work, published under her real name of Madeleine Wickham, came out when she was 24 and still working as a financial journalist.

Last year, Kinsella published a novella, “What Does it Feel Like?,” inspired by her cancer diagnosis and treatment, which also became a bestseller.

In April last year, Kinsella revealed she had been diagnosed with glioblastoma at the end of 2022 and was receiving treatment at University College London.

Araminta Whitley and Marina de Pass, her agents, told The Bookseller, a London-based industry publication: “Over the last three decades, her success has been truly international: she published thirty-four novels across adult, YA [young adult] and children’s publishing that have topped charts around the world, breaking records and defying expectations.”