Why the house in Doctor Who episode Knock Knock is even more significant than you think

Well, it sort of did – because TECHNICALLY, Blink was shot in the house next door, which has different owners despite being on the same property.

“It’s the same building, but the house is sort of in two halves,” episode producer Nicki Wilson told RadioTimes.com. “It’s kind of a semi-detached Gothic mansion, so Blink was actually filmed on the other half of the house.

The Fields House in Newport, South Wales

“The other half of the house is where Blink is filmed, and actually where we filmed the cellar for this episode.

Confusingly though, this doesn’t mean that Blink’s classic cellar scenes (where the Weeping Angels rounded on Carey Mulligan under a blinking lightbulb) were filmed in the same underground location as this week’s episode – because in the former case, the Weeping Angel attack was shot in studio. TV magic!

Still, whichever half you’re looking at, the Fields House has a storied TV history. At the time Blink was filmed at the location the house was empty and in need of restoration, and its slightly rundown interior also ended up doubling for another Steven Moffat-scripted story – Sherlock episode a Study in Pink, where it stood in for Lauriston gardens.

In more recent years the building was bought and refurbished (appearing on Nick Knowles restoration series Original Features), and since then it’s been able to double for more salubrious locations, including in another Sherlock episode (2012’s A Scandal in Belgravia), Casualty, High Hopes and once again Doctor Who, where it made a triumphant return for the 2014 festive special Last Christmas.

Specifically, the building’s dining room (which appears in this week’s Doctor Who when the Doctor and Bill’s housemates use it as a communal area and struggle with some shutters) was the room where Jenna Coleman’s companion Clara Oswald reunited with the Time Lord in her old age (see video above), only to find that she was actually suffering from a hallucination. Ah, memories.

Not that every scene this week was actually filmed in the Fields House, as Wilson went on to explain.

“This house, obviously we filmed in [the dining room], we filmed outside and we also filmed in the basement, the cellar scenes were in the house next door,” she said.

“And all the rest of it, the kitchen, the hallway, and the upstairs corridors and the bedrooms were all done on a house up in Usk. So it was great to be able to limit it to just those two locations.

She added: “I asked our designer to draw for the crew a map of our fictional house that showed where all of the different elements were over our two locations, just so that people were really clear on how that journey through the house worked.

“We wanted it to be really clear, so I hope that came across on screen.”

David Suchet as The Landlord and Pearl Mackie as Bill with Bill's housemates in Knock Knock

Said Usk house has itself apparently appeared in Doctor Who for yet another Christmas special – 2011’s The Doctor, the Widow and the Wardrobe – so frankly this whole week is steeped in nostalgia for fans.

Though it’s perhaps one cast member who found the whole filming experience the biggest trip down memory lane, with guest star David Suchet revealing when they began shooting that he had his own history with Fields House.

“Actually there’s a bit of a spooky story about David Suchet, because we brought him to this location, and he walked here and went ‘I’ve been here before,’” Wilson said.

“And it turns out that his brother had hired this as a holiday house one Christmas, and David had been and stayed here with his family, and nieces and nephews and everything.

"So yeah – it was a bit spooky."

A spooky old house that just keeps on cropping up when no-one expects it? We’d say this is DEFINITELY a case for the Doctor.

Doctor Who continues on BBC1 on Saturday evenings at 7.20pm