Isla Fisher is "heartbroken" over the death of author Sophie Kinsella.

On Wednesday, the Shopaholic series creator's family announced that she had passed away at the age of 55.

Kinsella, real name Madeleine Sophie Wickham, was diagnosed with glioblastoma - an aggressive form of brain cancer - in late 2022.

Following the sad news, Isla took to her Instagram Stories to honour the British writer, who penned 2000's The Secret Dreamworld of a Shopaholic and 2001's Shopaholic Abroad, which were adapted into the popular 2009 film, Confessions of a Shopaholic.

The Australian actress played Rebecca Bloomwood in the movie, with the feature co-starring the likes of Hugh Dancy, Joan Cusack, and John Goodman.

"Dear Sophie. You conjured Rebecca Bloomwood, a hilarious flawed dream of a comic character - and I was lucky enough to step into her shoes and speak your witty and brilliant words," she wrote in the caption. "My daughters grew up being read your books and love them to this day. My heart is broken. You are still my hero, and I'm grateful for you."

To conclude her emotional message, Isla added: "And though we won't meet again, your light and magic lives on in your incredible characters... I'm so heartbroken that you are gone."

Before adopting her pen name, Kinsella also published novels under her real name Madeleine Wickham, including her 1995 debut The Tennis Party.

The author, who went public with her health diagnosis last year, shared four sons and a daughter with her husband Henry Wickham.

Other industry figures to honour Kinsella include author Jojo Moyes, who described her friend as "one of the greatest people" and publisher Bill Scott-Kerr, who labelled the writer as "a unique voice".

"She has been such an unshakeable pillar of our publishing at Transworld for so many years that the thought of a year without a Sophie Kinsella to publish is inconceivable," he added. "On a personal level Maddy was the embodiment of joy, an extraordinarily clever, funny, sassy, impish, kind and generous collaborator who brought light into our lives. She was as part of this company as anyone, and we will all truly miss her."