Martin Shaw will reprise his role as the passionate detective, with Lee Ingleby also returning as his sidekick John Bacchus.
The four films will be set in 1968 - the first has been written by Peter Flannery and will feature guest performances from Roger Lloyd Pack (Only Fools and Horses) and Geraldine Somerville (Harry Potter).
'Gently With Class' will follow Gently and Bacchus as they investigate the death of a young girl found in the passenger seat of an aristocrat's upturned car.
Second film 'Gently Northern Soul' will focus on the racially-motivated murder of a young black girl. Written by David Kane (Sea Of Souls), the instalment will star Lenora Crichlow (Being Human), Eamonn Walker (Oz) and Maggie O'Neill (EastEnders).
Simon Block's third episode will focus on the kidnap of a middle class couple's adopted child, while the final film, again written by Flannery, sees a suspended Gently pursued by old enemies from his London Met days.
"Gently and Bacchus return to Durham and Northumberland, my home turf, with plenty more murders and cases to solve," said Flannery. "It's 1968 with huge changes in society at that time, and hopefully our series continues to give a real portrait of the age."
The four new Inspector George Gently films are currently shooting on location in Durham and the North East and will be shown on BBC One later this year.
> Inspector George Gently repeat grabs 3.6m
Watch the title sequence to Inspector George Gently below: