The Winds of Winter release date: George RR Martin says book will not be out before Game of Thrones season 6

'You’re disappointed, and you’re not alone'

A Song of Ice and Fire author George RR Martin is known for the long time he takes to write his lengthy fantasy novels (Getty Images)

George RR Martin, author of Game of Thrones, has said the latest addition to his popular series will be delayed because “the book's not done”.

The release date of The Winds of Winter, the sixth novel in Martin's A Song of Ice and Fire saga, was due to coincide with the launch of the franchise’s new TV series in April and will now miss the last deadline allowing the book to be published before the TV series begins.

Martin said although ”there’s a lot written, hundreds of pages, dozens of chapters”, he is still “months away” from completion, adding “and that’s if the writing goes well.”

In a blog post he said: “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 be more disappointed than me.

“But the book’s not done. Nor is it likely to be finished tomorrow, or next week.

“If truth be told, sometimes the writing goes well and sometimes it doesn’t, and that was true for me even when I was in my 20s.”

The sixth season of the popular HBO TV series based on Martin's books has already caught up with his storylines, and he admitted it may be strange for readers to find those who watch the TV series ahead of them with plot lines for the first time.

However, Martin also revealed The Winds of Winter and the sixth TV series would differ from each other. He said: “Some of the ‘spoilers’ you may encounter in season six may not be spoilers at all… because the show and the books have diverged, and will continue to do so.”

Suggestions the book would be finished in 2016 surfaced in October last year, after a Polish website reported a translator was asked to save time by the end of 2015 to translate the new book. Martin’s latest blog post has debunked these rumours.

The author, who has given many excuses for the delay, including tempting travel freebies and distraction, once said he hoped to have the ASOIAF saga finished by 1998.