'Game of Thrones' Data Stolen in HBO Hack, Network Calls Cyber Attack 'Unsettling, Disturbing'

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Winter may be coming a little faster than HBO had hoped.

The premium cable network experienced a cyber security hack over the weekend, resulting in a loss of some original programming. Part of what was leaked, hackers claim, is written material allegedly from Game of Thrones's upcoming fourth episode this season, with more promised, according to EW.

SPOILERS: 'Game of Thrones' Longest-Kept Secret Finally Revealed! Plus, Cersei Gets Wicked Revenge & Dany and Jon Meet!

HBO confirmed the hack Monday, telling ET in a statement, "HBO recently experienced a cyber incident, which resulted in the compromise of proprietary information. We immediately began investigating the incident and are working with law enforcement and outside cybersecurity firms."

"Data protection is a top priority at HBO, and we take seriously our responsibility to protect the data we hold," the network added.

ET has also obtained a letter from HBO chairman and CEO Richard Plepler to his employees, in which he calls the breach "disruptive, disturbing, and unsettling."

WATCH: 'Game of Thrones' Teases the Epic Meeting We've All Been Waiting For!

"As most of you have probably heard by now, there has been a cyber incident directed at the company which has resulted in some stolen proprietary information, including some of our programming," Plepler revealed. "I can assure you that senior leadership and our extraordinary technology team, along with outside experts, are working round the clock to protect our collective interests. The efforts across multiple departments have been nothing short of herculean. It is a textbook example of quintessential HBO teamwork. The problem before us is unfortunately all too familiar in the world we now find ourselves a part of."

As has been the case with any challenge we have ever faced, I have absolutely no doubt that we will navigate our way through this successfully," the CEO added.

EXCLUSIVE: Will Arya and Sansa Stark Ever Reunite? Sophie Turner Reveals the Truth!

Meanwhile, episode three of Game of Thrones was not short on major plot points, including the final meeting of (SPOILERS) Jon Snow and Dynaerys Targaryen, aka Ice and Fire!

Watch the video below for a (SPOILERS) recap.