Producers have promised it will be "much more than a 'making of'" documentary.
The announcement added: "This is a funny, heartbreaking story, told with wit and intimacy, about the bittersweet pleasures of what it means to create a world -- and then have to say goodbye to it."
Meanwhile, Emilia Clarke recently admitted she "broke down" after filming her final scenes as Daenerys Targaryen.
She said: "I started to do a little speech, not because I'm a pretentious actor, but because every time we said goodbye to a character, showrunners David [Benioff] and Dan [Weiss] would give us a gift and the crew would be around and everyone would stop and you'd sort of say a few words and it was really beautiful.
"I mean, I got three words in before I just completely broke down. You just hold it in and you're holding it in and you're holding it in, and then I just burst into tears like a complete idiot.
"Then we cracked open the champagne, but it was then that I realised that alcohol is a depressant! So it was less a celebratory champagne, it was more kind of like, 'We did it! We got to the finish line!' "