The 46-year-old actress discussed the movie in an interview with E! News on Saturday. Zellweger played the title character in Bridget Jones's Diary (2001) and Bridget Jones: The Edge of Reason (2004), and will reprise Bridget in the forthcoming sequel.
"I'm having a good time," she told the website. "It's really a nice reunion with old friends. And it's always wonderful to be back in London and I love this character so it's been a real treat to get to revisit it again ... I'm really glad to be doing it."
Colin Firth will return as Mark Dancy, whom Bridget got engaged to in The Edge of Reason. Universal Pictures U.K. released a first photo of Zellweger in character this month, and newcomer Patrick Dempsey also posted a picture on location.
The Bridget Jones movies are based on the Helen Fielding book series, and earned a combined $544 million at the box office. Zellweger last appeared in My Own Love Song in 2010, and will next star in The Whole Truth with Keanu Reeves.