Game of Thrones: George RR Martin might add eighth book to Song of Ice and Fire series

The US author's editor has hinted that another novel could still be added

George RR Martin's A Song of Ice and Fire novels are the basis for HBO's Game of Thrones (Getty Images)

George RR Martin fantasy novel series, A Song of Ice and Fire, may be extended to eight books rather than the confirmed seven, reports suggest.

The author’s editor Anne Groell hinted at the possibility during a Q & A session with fans, many of whom follow Game of Thrones, the hit HBO TV series based on the books.

Groell recalled how Martin’s epic saga began as a trilogy, before evolving into a longer series after she pushed for “seven books for seven kingdoms”.

Since then Groell has learned that, technically, there are eight kingdoms, “all having to do with who has annexed what when Aegon the Conqueror landed in Westeros”.

Groell discovered more about Martin’s imaginary setting while editing The World of Ice and Fire, a forthcoming companion book to help fans navigate the expansive areas described in the novels.

Martin’s most recent instalment, A Dance with Dragons, was published in 2011, but Martin is famous for long gaps between releases.

He has spoken previously of finding it hard to keep up with fans’ demands, while Groell has tried “multiple times” to encourage him to work on the road. “He is one stubborn man and very set in his ways,” she revealed.

At present, Martin is working on the sixth book in the series, The Winds of Winter, which has yet to be completed. “When I have a (publication) date, you will have a date,” Groell promised.

In March, Martin dropped fans the surprise of a new chapter, “Mercy”, which is still available to read on his website.

Despite speculation over an eighth, Martin is under contract for just seven books, with UK publisher Jane Johnson unable to confirm whether or not there would be more.

“In all honesty only George knows how many books there will be in the series and he’s not saying,” she told the Guardian. “Indeed, at this stage of his writing, with the many branching pathways of the characters’ stories still to intersect, he may not know.”

Johnson then admitted that the chance of Martin tying up all the loose ends in only two more books seems unlikely. “But if George continues to kill off characters in his usual ruthless fashion it could easily be over in the planned seven books!” she said.

Martin has left his future plans open but insists he is not considering an eighth novel "right now". "I write the stories and they grow," he told Entertainment Weekly. "I deal with certain things and sometimes I find myself not at the end of a story. But first I have to finish book six."