The revelation came as extracts of Fielding's latest Bridget Jones's Diary, "Mad About The Boy", were published in the Sunday Times Magazine.
Fielding began the series as a British newspaper column in 1995 before selling 15 million copies of the first two novels, which were made into Hollywood films starring Renee Zellweger as Bridget and Colin Firth as the aloof Darcy.
Portrayed as a stereotypical 1990s London thirtysomething worried about her weight, smoking and alcohol intake, Bridget struck a chord with women of her generation.
Bridget's new adventures as a 51-year-old single mother show her five years after Darcy's death, meeting new 30-year-old toyboy boyfriend, Roxster, on Twitter.
In one extract, Jones agonises over whether to take her now boyfriend to a party.
"Crucially, it might put Roxster off me, to be surrounded by old people at a sixtieth birthday party, and make some sort of completely unnecessary point about how old I am though of course I am MUCH younger than Talitha. And frankly, I refuse to believe how old I actually am," she writes.