Kara Tointon reveals "nerve-wracking" nude scene in The Halcyon

What do you do if your boss walks in and is shocked to find you stark naked, chilling in his bathtub? If you're Kara's feisty character Betsey Day, you yell, "Bloody hell don't they teach you to knock?!" then stand straight up and demand he pass you a towel.

The scene is shot from behind, with The Halcyon hotel's owner Lord Hamilton (The Crown and Victoria's Alex Jennings) looking stern but unsure how to deal with the situation as he hovers in the doorway.

"That was interesting because it's not such a sexy scene; it's just her standing up with nothing on. It made it more nerve-wracking, actually," Kara said.

But with judiciously-applied "sticky bits", the former Strictly champion overcame her worries: "Honestly, it was fine. And it was only Alex there and he's lovely."

The Halcyon tells the story of a glamorous London hotel in the early, uncertain days of the Second World War. Betsey is the singer for the hotel's Sonny Sullivan Band, "the alleycat of the piece", with straight-talking charm and a down-to-earth attitude.

The bath scene establishes her personality in just a few seconds.

"I didn't argue against that scene," Tointon revealed. "It is a funny scene, that's why I didn't.

"Sometimes when those things come up you question whether it's needed, but I absolutely thought it was great because it introduces you to someone in one swoop: that she doesn't care, and that's what she's about. She's fun."

The drama flits between the aristocratic Hamilton family (upstairs) and the staff (downstairs), headed by Steven Mackintosh's Mr Garland, with plenty of intrigues and betrayals and family rows.

But there's an elephant in the room: can The Halcyon be the new Downton Abbey?

"I think it's just a compliment for anyone to say that it could be a new Downton," Kara said. "A sexier Downton... it's like an upstairs-downstairs feel on speed."