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It's going to be even longer before the next "Game of Thrones" book arrives.

In a post on his personal blog, "Game of Thrones" author George R.R. Martin had some disappointing news for fans: He wasn't able to finish the next book in the series, "Winds of Winter", by the end of 2015. In fact, Martin warned it could be several more months before he's able to deliver the novel.

Here's what Martin said:

THE WINDS OF WINTER is not finished.

Believe me, it gave me no pleasure to type those words. You're disappointed, and you're not alone. My editors and publishers are disappointed, HBO is disappointed, my agents and foreign publishers and translators are disappointed... but no one could possibly be more disappointed than me. For months now I have wanted nothing so much as to be able to say, "I have completed and delivered THE WINDS OF WINTER" on or before the last day of 2015.

The hope was that Martin would be able to finish "Winds of Winter" in time for the premiere of season 6 of the HBO show, which has mostly caught up to the books.

Martin said he simply ran out of time to finish the book. His original deadline was October 31, 2015. But when it became clear he couldn't meet it, his editors and publisher extended the deadline another two months, which would still give them time to get the book out in time.

But Martin still missed his deadline, and left things very vague as to when he thinks he'll be able to finish the book.

Luckily, Martin assured everyone that HBO and the publisher of his book had a plan in place just in case this happened. The show's producers and writers have the entire story sketched out. But it's still not an ideal situation for fans of the books who are concerned that the show is going to continue the story before the books can.