The 49-year-old American actor posted a photo of himself in the UK where he is gearing up to star in the big-screen sequel with Renee Zellweger and Colin Firth, reported Entertainment Weekly.
"Nice to be working in England. Renee and Colin are an absolute joy to work with," he captioned the photo.
Details about Dempsey's character are yet to be revealed.
Directed by Sharon Maguire, the release date for "Bridget Jones's Baby" has not been announced yet.