Game of Thrones fans are having an absolute field day over a rogue Starbucks cup that made an appearance on last night’s GoT episode.

While it has been confirmed by HBO that the cup was indeed a major oversight, Starbucks is forevermore part of GoT history.

HBO released a tongue-in-cheek response to the error: “In response to inquiries from those who saw a craft services coffee cup in Sunday night’s episode of Game of Thrones, HBO states, ‘The latte that appeared in the episode was a mistake. Daenerys had ordered an herbal tea.’”

Thanks to the major blunder, however, the global coffee company received plenty of free advertising from the production mistake, which was magnified due to the fact the latest season of GoT took two years to film.

Stacy Jones, CEO of Hollywood Branded, a company which specilaises in product placement, told MarketWatch that HBO doesn’t accept payment for product placement in its show because customers are subscribing to an ad-free experience when signing up for the premium cable network.

She said, however, if GoT decided to include an ad for Starbucks, then placing the cup in front of Daenerys (a character on the show), would cost $250,000 in product-placement costs.

Jones said: “We’re saying this is a Super Bowl–sized television series. We’re comparing this to a ‘Transformer’ franchise, and ‘Transformer’s’ deals of this type are around $250,000 to $1 million.”

Due to the fact the cup was only on screen for a few seconds and no one was seen using it, Jones said it would be on the lower end of product placement fees.

Jones said the PR value of the slip-up is up to $1 million in word-of-mouth.

She said: “It doesn’t even matter whether the brand on that cup is Starbucks or not, because so many people think that it is, and hundreds of thousands of people are already commenting on it. I would say the value for Starbucks on this scale is well into the millions, plural, of dollars.”

According to a Twitter spokeswoman, Starbucks tweets are running at 10 times their average hourly tweets for a Monday morning (US time). She said: “There have been more than 310,000 tweets today, and I’d say on an average normal day there are usually less than 100,000 tweets.”

Check out some of the tweets below.

You might be having a rough Monday, but at least you weren't the person who left a Starbucks cup in Game of Thrones pic.twitter.com/GgP1Knz8uV

— Betches (@betchesluvthis) May 6, 2019

Give me the oral history of the Starbucks cup in the frame!!!! pic.twitter.com/4CkFJXFQ91

— Jordan Crucchiola (@JorCru) May 6, 2019

Dany on her way to king’s landing w her iced coffee in her starbucks cup pic.twitter.com/jO4z4lVm5a

— Benjo Juco (@baenjojuco) May 6, 2019

My nephew Lyle is upset about a Starbucks cup appearing in his ridiculous sword fight program.

The real issue is NO COASTER. pic.twitter.com/Yt0BbmYwF6

— Myrna Tellingheusen (@PearlsFromMyrna) May 6, 2019