'Bridget Jones's Baby' bosses never printed the ending of the movie in the scripts.

Renee Zellweger

Renee Zellweger

Filming on the highly-anticipated third movie in the franchise was kept shrouded in secrecy and the final scenes were deliberately ambiguous so people wouldn't find out whether the eponymous heroine - who is played by Renee Zellweger - would end up with Mark Darcy (Colin Firth) or newcomer Jack Qwant (Patrick Dempsey).

Renee explained: "They filmed ambiguous endings. The script says, 'X stands next to Bridget, Y stands next to Bridget.' But no one ever knew who X and Y were. And the script continued that way. It was not printed. No ending was ever printed in the scripts.

"The guys just changed places so we got both things done. So whoever was there with the cellphone camera got both and that was that."

The 47-year-old actress came out of a six-year hiatus to make the movie but was apprehensive about returning to the franchise as she didn't want to taint the character.

She told Heat magazine: "I wanted it to matter and if you make a third film based on a character that is beloved to so many people, you want to be careful with it, and I felt a responsibility to (author) Helen Fielding.

"I wanted to know, in the process, that the story we told was based on something substantive.

"And that it was true to the tradition of this character and what she represents."

Renee thinks Bridget has remained popular because she is "inspiring" and "authentic".

Asked how she relates to her alter ego, she said: "Mostly her failures and that she gets back up. She is inspiring but no matter how much she tries to meet her own personal ideals or standards, she always comes full circle to be OK with what she is as an authentic person."