Show bosses were left trying to cover their tracks when many pointed that there probably isn’t a coffee shop in Westeros and the production blunder soon went viral.
While it has since been erased from the scene for all future broadcasts, it’s not the first time a modern object has turned up in a period drama...
Braveheart and the Ford Mondeo
This 1995 film starring Mel Gibson told the story of a 13th-century Scottish warrior, so quite what a Ford Mondeo was doing in the back of a shot during a horseback battle scene is anyone’s guess.
Gladiator and the gas cylinder
Spotting various errors in this Russell Crowe epic has become somewhat of a sport among film fans, but this blunder is one of the more blink-and-you’ll-miss-it ones.
During one of the famous battle scenes, a Roman chariot is flipped onto its side and a gas cylinder can be seen. The thing is, gas cylinders were not invented until about 1600 years after the film was set.
Downton Abbey and the TV aerial
Downton Abbey filmed on location at various points during its run, which meant having to transport many places back 100 years in time.
However, one error that many viewers noticed during one early episode was the appearance of a TV aerial on top of a house. With the series set in 1912, it was a full 15 years prior to television even being invented.
Downton Abbey and the road markings
Another detail that producers forgot to cover up during a shoot in a rural village was a double yellow line, which didn’t actually appear on UK roads until 1960.
Downton Abbey and the plastic water bottle
Technically, this blunder never made it to air, as it appeared in a photograph distributed to press to promote the show in 2014, but it is certainly Downton Abbey’s most famous gaffe.
The picture saw a plastic water bottle appear on the mantelpiece behind cast members Hugh Bonneville and Laura Carmichael in character as Robert Crawley, Earl of Grantham and Lady Edith Crawley.
The cast saw the funny side though, later posting a photo of them all backstage holding plastic bottles.
Poldark and the burglar alarm
Likewise, this Poldark gaffe also appeared in a promotional shot for the BBC drama.
Despite being set in the 18th century, a modern burglar alarm could be seen on the front of one of the houses in the background.
The Crown and the modern flats
On the surface, there might not look to be too much wrong with this shot taken from hit Netflix series The Crown.
But bearing in mind the series from which this still is taken from was set in the 1950s, the modern flats/office building at the right-hand end of the street begin to look a little out of place for the time.
Call The Midwife and the microphone
Last time we checked, microphones were not a key part of a nunnery - especially back in the 1950s. But an errant one was seen in a shot next to Sister Monica Joan in the BBC drama in 2015.