Game of Thrones's next episode has been pirated and shared online in the latest leak to hit the fantasy TV series.
However, this time, the source of the leak was not hackers or thieves, but rather the show being mistakenly released on to its broadcaster's streaming platform too early.
The episode, titled Death is the Enemy, has since been withdrawn, but not before it was copied.
Twin Peaks suffered a similar error recently.
A spokesman for HBO Europe blamed an unnamed contractor for the most recent blunder.
"We have learned that the upcoming episode of Game of Thrones was accidentally posted for a brief time on the HBO Nordic and HBO Espana platforms," Tom Krogsgaard Nielsen told the BBC.
"The error appears to have originated with a third-party vendor, and the episode was removed as soon as it was recognised.
"This is not connected to the recent cyber-incident at HBO in the US."
Reports indicate that high-definition footage from the episode was initially posted to YouTube, the Daily Motion, Instagram and other social media sites.
Although it has since been removed, different copies of the complete 66-minute show are still being shared on several file-sharing platforms, according to the news site Torrentfreak.
HBO has suffered a series of security setbacks over recent weeks.
Unidentified hackers have released Game of Thrones scripts, company documents and unbroadcast video episodes of some of HBO's other shows, including Curb Your Enthusiasm and Insecure.
They claim to have stolen 1.5TB of data in total.
In a separate incident, pirated copies of the 6 August episode of Game of Thrones were spotted online several days earlier in the week, featuring an Indian broadcaster's logo.
Four people have since been arrested, three of whom work for a Mumbai-based company that stored and processed the show for an online streaming service.
HBO is not the only broadcaster to have been caught out by its own technology.
Sky Deutschland accidentally uploaded episode 14 of Twin Peaks: The Return to its streaming platform on 7 August, instead of episode 13.
It blamed "wrong labelling of the broadcasting file" for the error, which is somewhat ironic as one of the themes of the series is mistaken identities.
Although some viewers shared spoilers and screengrabs to Reddit, reports at the time suggested the episode had not been pirated as a consequence.
Ed Sheeran's Twitter page reappeared on Tuesday with a spring clean of old tweets after a brief disappearance prompted speculation that the singer had quit the social media platform after the mixed reaction to his cameo on TV show "Game of Thrones."
Sheeran's Twitter account, which boasts 14 million followers, appeared to have been deactivated on Monday. On Tuesday, it was live again, but many of Sheeran's 30,000 tweets, including recent posts and comments from fans, had been deleted.
A representative for the British singer did not immediately respond to requests for comment.
Sheeran was active on Instagram on Tuesday, posting a photo of a cat and a picture from the set of "Game of Thrones." On Sunday he also posted photos and a video of his “Game of Thrones” cameo.
Sheeran's scene on Sunday's HBO medieval fantasy series, in which he plays a singing soldier who encounters character Arya Stark, garnered mixed reception from avid "Game of Thrones" fans. Many criticised his cameo as distracting in a show that does not usually use celebrities.
The 26-year-old singer, whose latest album, "Divide," topped charts in the United States and Britain earlier this year, has been vocal about his dislike of Twitter.
He told Britain's Sun newspaper earlier this month that it was "nothing but people saying mean things" and that he had stopped using the platform regularly.
"Game of Thrones" returned for its season seven premiere on Sunday, ending a longer-than-usual wait for fans craving its unique weekly offer of sex, violence and dragons.
HBO had delayed production, meaning four more months of anticipation ahead of the season debut -- already one of the television events every year across the world.
But viewers were not disappointed, taking to social media in the thousands to express delight at the explosive start opening, the arrival of dragon queen Daenerys Targaryen in Westeros and a widely-hyped cameo by pop sensation Ed Sheeran.
"There are very few shows that can deliver as much action and excitement as the season six 'Game of Thrones' finale, and there are perhaps even fewer shows that can make a table-setting episode this much fun," the Hollywood Reporter said after the premiere.
"So it's all the more bittersweet that not only is winter here, but the end is in sight."
The debut episode, entitled "Dragonstone," saw evil Cersei Lannister (Lena Headey), now ruler of the Seven Kingdoms, making alliances that threaten newly-anointed King of the North Jon Snow (Kit Harington).
Trained poisoner and throat-slitter in chief Arya Stark (Maisie Williams) exploded out of the blocks in a shocking opening by taking vengeance on the killers of her family at the infamous Red Wedding.
The comic relief was provided by multiple Grammy-winning Sheeran in a cameo as a soldier who sang a ditty -- a "new one," apparently -- about a woman's hand.
His appearance started a torrent of memes and excited comments from fans on Twitter, but not everyone was pleased to see him.
Variety magazine called the cameo "ridiculous" while one fan on Twitter quipped: "If Arya kills Ed Sheeran it'll be worth it."
"Game of Thrones" tells the story of noble families vying for control of the Iron Throne, all the while keeping one eye on the "White Walkers" leading hordes of the undead toward an invasion from the North.
The show, which has more Emmy Awards than any other narrative series and pulls in more than 20 million US viewers per episode, moved beyond George R.R. Martin's "A Song of Ice and Fire" novels in season six.
It is due to run for a shortened seven episodes this year before returning for a six-episode final season.
"As per every premiere episode of 'Game of Thrones,' the pace is slow," wrote Lorraine Ali in the Los Angeles Times.
"Setting up each new carefully constructed season -- the complex weave of story lines, the huge cast, the breathtaking locations -- takes time."
But she concluded that showrunners David Benioff and D.B. Weiss had "pulled it off once again, if not with a bit more humour than in previous seasons."
Game of Thrones is leading the Emmy award nominations with 24 nominations.