George RR Martin to release 'Game of Thrones' prequel

Author George R.R. Martin will release Game of Thrones prequel Fire & Blood later this year.

It will serve as a prequel to the A Song of Ice and Fire book series that is the narrative for HBO's Game of Thrones.

But Fire & Blood and its forthcoming companion won't be novels.

According to Martin's publisher Ballantine Bantam Dell, Fire & Blood will be "the definitive history of the Targaryens in Westeros and chronicles the conquest that united the Seven Kingdoms under Targaryen rule through the Dance of the Dragons: the Targaryen civil war that nearly ended their dynasty forever."

Martin discussed the new prequel on his blog saying it's a "hefty book" with a 1,000-page manuscript.

Unfortunately fans of Martin's long-awaited book The Winds of Winter won't be getting it this year.

In a statement, Martin said: "No, winter is not coming... not in 2018, at least," he wrote. "You're going to have to keep waiting for THE WINDS OF WINTER. ... I do want to stress...indeed, I want to shout... that FIRE & BLOOD is not a novel. This is not a traditional narrative and was never intended to be…let's call this one 'imaginary history' instead. The essential point being the 'history' part. I love reading popular histories myself, and that's what I was aiming for here… As for me, I'm returning once again to THE WINDS OF WINTER."

The Game of Thrones author has not yet finished the novel which will follow 2011's A Dance With Dragons in the series.

Fire & Blood is due November 20 via Ballantine Bantam Dell.

The new and final season of Game of Thrones will air on HBO in 2019.