Renee Zellweger was said to be returning to her famed role as the lovable bachelorette in the latest instalment of the popular franchise last year.
However, according to The Sun, the 54-year-old actress only has a small window in which to film the movie, and time is rapidly running out as production is held up by the strike.
A source told the publication: “It’s a nightmare for film bosses. It’s taken ages to get everyone on board with Bridget Jones 4 and now the strike means it’s in jeopardy.
“Renee is one of the biggest names in Hollywood so has already signed up for multiple films in the coming years.
“She only had a tight window to shoot Bridget and the strike means she could totally miss it.”
The films, launched in 2001 and based on the best-selling book Bridget Jones’s Diary, have grossed almost £1 billion at the box office with the first instalment earning Zellweger a best actress Oscar nomination.
The last film, Bridget Jones’ Baby, was released seven years ago, and saw Bridget pregnant and trying to work out who the father was.
Author Helen Fielding confirmed she was working on the fourth film last October, saying it would be based on her 2013 book Mad About the Boy.
Fielding said: “Yes I’m working on it and I really hope it will happen. Every film that gets made is a miracle – it’s really difficult to make films happen and to make them good. But I’d love to see it on the screen.”