The Scott and Bailey star will portray Anne Lister, a 19th century Halifax woman who embarked on a determined and passionate courtship with another woman.
Along with writer Sally Wainwright, the actress visited Shibden Hall to see the surroundings the television drama will be set and seemed very impressed with the setting
Posting on her Instagram account she said: "Amazing day up at Shibden Hall with Sally Wainwright and the Gentleman Jack team. It's so worth a visit as the hall is fascinating and the parkland is glorious.
"Cafe and children's play park make it a family outing dream."
The series will be set in 1832, Gentleman Jack, originally called Shibden Hall, is the epic story of landowner Anne Lister.
Returning after years of exotic travel and social climbing, Anne determines to transform the fate of her faded ancestral home, Shibden Hall, in Halifax.
The series will start filming next year. It’s a Lookout Point production for the BBC and co-produced with HBO.