Bridget Jones (Renée Zellweger) is ecstatic about her new relationship with Mark Darcy (Colin Firth). However, Bridget's confidence is shattered when she meets Mark's assistant, the beautiful, slim, quick-witted Rebecca Gillies (Jacinda Barrett). At her job on TV morning show Sit-Up Britain, Bridget crosses paths with her ex, Daniel Cleaver (Hugh Grant), and is offered a position alongside Cleaver in a new travel series. Bridget initially refuses, declaring Daniel a "deceitful, sexist, disgusting specimen of humanity," but eventually signs on, despite her friends' misgivings.
Bridget is delighted when Mark invites her to his "Law Council Dinner," believing he will propose afterward. However, a series of fashion/cosmetic mishaps make the evening a debacle, culminating in the team trivia quiz: Bridget makes a critical error on a question about Madonna, which Rebecca Gillies wins, leaving Bridget thoroughly deflated.
After the dinner, Mark and Bridget argue and she leaves in a huff. Mark goes to Bridget's apartment, apologizes, and tells her he loves her for the first time. Later that night, Mark invites Bridget on a ski holiday to Lech, Austria. On the slopes, she learns Rebecca recommended the vacation spot and that she is there as well with a few other colleagues. Bridget has a pregnancy scare since her period is late, but after an argument over the upbringing and education of their future children, the pregnancy test proves negative. Returning home, Bridget and Mark attend a lunch with their parents, where Bridget is hurt by Mark's dismissal of their prospective marriage.
Bridget overhears a suspicious message from Rebecca on Mark's answering machine and dissects it with her friends, who advise her to confront him; Bridget does, Mark refuses "to dignify the question with an answer," and Bridget breaks up with him. She travels to Thailand with her friend, Shazza (Sally Phillips) and Daniel Cleaver to film "The Smooth Guide." Bridget and Daniel visit several exotic locations and flirtily reconnect, but Bridget's trust in Daniel is again demolished by the arrival of a prostitute he ordered, and she realizes he has not changed his boorish ways.
Shazza has a fling with the much younger Jed (Paul Nicholls), who gives her an ivory tusk as a gift to take back to Britain, which winds up in Bridget's bag. When security dogs at the airport detect a large stash of cocaine inside the tusk, Bridget is arrested and sent to a Thai prison and locked in a cell with almost 50 other Thai female inmates. Feeling low and scared but glad at the friendliness of the inmates, Bridget shares relationship advice with the other inmates and teaches them to sing and dance to Madonna's "Like a Virgin."
Mark arrives to tell Bridget that her release has been put in motion. After confirming Jed as the true perpetrator and that Bridget "spent the night" with Daniel Cleaver, he declares that her sex life does not interest him; Bridget does not correct his presumption, and he departs, leaving Bridget certain he no longer loves her. Back in Britain, Mark confronts Daniel for abandoning Bridget in Thailand, and they fight outside an art gallery in Kensington Gardens. Daniel swears off Bridget for good and sarcastically suggests to Mark, "Why don't you just marry her?"
Bridget arrives at Heathrow Airport as an international human rights celebrity. She is greeted by her parents, who have been busy planning their vow renewal ceremony. At home, Bridget is surprised by her friends, who reveal that Mark personally tracked down the drug trafficker Jed, secured his custody and extradition, and forced him to admit Bridget's innocence. Hopeful that Mark still loves her, Bridget immediately runs to his house. She finds Rebecca there and assumes she is romantically involved with Mark, but Rebecca reveals that she is actually infatuated with Bridget and kisses her; though flattered, Bridget politely turns her down.
Bridget confronts Mark at his legal chambers and asks him to give her another chance. Mark proposes to Bridget and she accepts. The film ends with Bridget's parents renewing their vows and Bridget catching the bouquet.
Renée Zellweger as Bridget Jones
Colin Firth as Mark Darcy
Hugh Grant as Daniel Cleaver
Gemma Jones as Mrs. Pamela Jones
Jim Broadbent as Mr. Colin Jones
Celia Imrie as Una Alconbury
James Faulkner as Uncle Geoffrey
Jacinda Barrett as Rebecca Gillies
Sally Phillips as Sharon "Shazza"
Shirley Henderson as Jude
James Callis as Tom
Neil Pearson as Richard Finch
Donald Douglas as Admiral Darcy
Shirley Dixon as Mrs. Darcy
David Verrey as Giles
Jeremy Paxman as Himself
Ian McNeice as Quizmaster
Jessica Stevenson as Magda
Paul Nicholls (special participation) as Jed
Wolf Kahler as Commentator
Catherine Russell as Camilla
Ting-Ting Hu as Thai prostitute
Jason Watkins as Charlie Parker-Knowles
Vee Vimolmal as phrao
Patrick Baladi as Flight attendant
Neil Dudgeon as Taxi driver
Pui Fan Lee and Melissa Ashworth as Thai jail girls
based on Helen Fielding's 1999 novel of the same name
the sequel to Bridget Jones's Diary (2001)