The ghostly inhabitants of the mansion, Button House, come from a variety of historial periods, ranging from prehistoric man right through to the present day.
Ritchie and Smith-Bynoe play Alison and Mike, a modern couple who recently had a baby in the final series.
The new film will be made at the same site as the TV series – West Horsley Place in Surrey.
It will be directed by Simon Hynd, whose other TV credits include Ghosts, Motherland and There She Goes.
Eva Yates, director of BBC Film added: “We are overjoyed to be bringing our beloved Ghosts back once again, this time for a hilarious and cinematic adventure, for the enjoyment of audiences on big and small screen alike.”
Ghosts was also made into a hit US version, which is currently in its fifth season, with a sixth already commissioned.
The series and format, distributed by BBC Studios, has also been licensed in six territories, most recently in Czechia, with local versions also produced in France, Germany, Australia and Greece.
BBC Film, Lionsgate and BBC Studios gave the green light to make the feature film to Monumental Television, part of ITV Studios.