Martin tweeted about it and wrote a blog post as well.
The book is titled Fire & Blood—which certainly sounds very Thrones-ish—and here's Martin's from his blog:
No, winter is not coming… not in 2018, at least. You’re going to have to keep waiting for THE WINDS OF WINTER.
You will, however, be able to return to Westeros this year, as I suggested back over on Live Journal.
Archmaester Gyldayn has at last completed and delivered the first half of his monumental history of the Targaryen kings of Westeros, FIRE & BLOOD, and Bantam Spectra and HarperCollins Voyager will be releasing the hardcover on November 20, I am thrilled to say.
C'mon, man. Fire & Blood is essentially a history of main families in Thrones, and it takes place 300 years before the current timeline.
Naturally, Twitter had some reactions.
Twitter always has reactions, of course, but Game of Thrones fans are another level, and they want blood, but not Fire & Blood. Obviously.
George R.R. Martin should stay away from Medieval Times restaurants and Renaissance Faires from here on out. For his own safety.