"A Song of Ice and Fire" author George R.R. Martin, whose novels inspired HBO's "Game of Thrones," has not completed his sixth book in the fantasy series, which means "The Winds of Winter" will not be published before the next season of "Game of Thrones." The HBO TV series is scheduled to return in April, and it sounds as if "The Winds of Winter" is still nowhere close to being completed.

Martin made the announcement himself on his blog.

"Believe me, it gave me no pleasure to type those words," he wrote. "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.

"But the book's not done."

Martin would give no indication as to when he believes the sixth book will be done, but given his writing history, fans should not expect "The Winds of Winter" anytime soon.

HBO's "Game of Thrones" will return for its sixth season in April.