‘You never really stop looking for the secrets some houses keep,” says Tuppence Middleton. Mystery certainly swirls around the homes at the heart of both her new dramas. On the big screen, the 35-year-old actress reprises the role of a lady’s maid in Downton Abbey: A New Era, in which Lady Grantham (Maggie Smith) reveals that a man from her past has bequeathed her a villa on the French Riviera.

On the small screen, she stars in ITV’s four-part domestic thriller, Our House, opposite Line of Duty’s Martin Compston. Middleton plays Fi, a woman who comes home one day to a nightmare: all her belongings have, inexplicably, been stripped from her family’s beautiful suburban house and removal men are hauling in boxes for a couple who claim to be the new owners.

“Her furniture is gone. There are only rectangular marks on the walls where her children’s pictures were hanging. She can’t reach her husband on the phone,” explains Middleton. “These total strangers have her keys and a screenshot of her signature on documents she’s never seen. Everything she knew rationally and felt emotionally is snatched away from under her.” It’s only through a series of plot-twisting flashbacks that viewers come to make sense of how unstable her middle-class lifestyle really is.

Playing such “a contemporary everywoman” was a welcome departure for Middleton, who notes that she has “mostly been offered jobs in costume dramas” (such as War & Peace and Downton Abbey) “or science fiction” (Black Mirror, Sense8, Philip K Dick’s Electric Dreams). “Does that mean I don’t look quite at ease in ‘the now’?”

In a sense, it does feel as though Middleton is Zooming me from the past. There’s a sepia-photograph quality to her soft, oval face and bright brown eyes. She’s dressed in a demure chiffon blouse with a high neckline and long, ruffled sleeves. Over her shoulder I can see her home is decorated in a firmly period style – all mahogany furniture, white walls and iron radiators.