© Rex Features
The Northern Lights pair will begin filming with the rest of the cast in Rochdale from next Monday, a BBC spokesperson told DS.
Philip Martin Brown, who plays Grantly Budgen in the show, broke the news to fans on his Twitter page.
While Green and Benton have committed to the drama for two series, their characters have not yet been revealed.
Waterloo Road will return to BBC One for its sixth series in the autumn.
