Colin Firthin the movies, has died in between the second and third instalments.
The snippets explain that fictional "singleton" Bridget married Darcy and had two children with him before his death.
Fielding's first Bridget Jones book for 14 years focuses on the character as a 51-year-old, five years after her husband's death.
It sees her meeting a 30-year-old toy boy called Roxter via social networking site Twitter.
The cause of Darcy's death will apparently only be revealed as a flashback later in the book - which will be [uuid=bb305d45-ddb6-4b94-8469-15137a93d28b]published on 10 October[/uuid].
Upset fans have been voicing their unhappiness with the shock twist via Twitter.