The revelation emerged when extracts of the latest instalment in the Bridget Jones series were printed in the Sunday Times magazine.
The new book, Mad About The Boy, finds Bridget - fifteen years on from the last book - a widowed 51-year-old mother of two children reeling from the loss of her beloved Mr Darcy.
*** Watch a tribute to the fictional couple below ***
True to form, Bridget is obsessing over her appearance - and struggling with the new challenge of wrinkles.
But middle age hasn't stopped the ever alluring Bridget from attracting admirers, and she is enjoying an affair with a 30-year-old tomboy called Roxster while also grappling with being single parent to Mabel and Billy after Mark's death 5 years before.
It is not yet known how Fielding chose to kill off barrister Mark, but the news came as a blow to thousands of fans who had enjoyed seeing the couple get together after a series of complications in the first two books and had hoped for a happy ever after.
One user, Kitty Eisele, wrote 'Mark Darcy is DEAD? V. UPSETTING. Alcohol, cigarettes and calories consummed: immeasurable.' while another, Sammie, wrote 'Okay so mark Darcy is dead in the new Bridget jones book - I am not reading it.'
The first Bridget Jones book was published in 1996, and followed protaganist Bridget as a 30-year-old singleton in London looking for love while chronicling a series of hilarious mishaps and neurosis.
Bridget became an unlikely heroine for many women and her love story with Mark Darcy encaptured readers.
The following book was released three years later and the books were turned into films with Renee Zellweger playing Bridget and Colin Firth as the gorgeous Mr Darcy.