“How will it all end? I hear people asking,” Martin asked rhetorically. “The same ending as the show? Different? Well … yes. And no. And yes. And no. And yes. And no. And yes.” You can almost hear the fans across the world screaming at their laptops in frustration.
Fortunately for them, he expanded on those thoughts:
I am working in a very different medium than David and Dan, never forget. They had six hours for this final season. I expect these last two books of mine will fill 3000 manuscript pages between them before I’m done … and if more pages and chapters and scenes are needed, I’ll add them. And of course the butterfly effect will be at work as well; those of you who follow this Not A Blog will know that I’ve been talking about that since season one.
There are characters who never made it onto the screen at all, and others who died in the show but still live in the books… so if nothing else, the readers will learn what happened to Jeyne Poole, Lady Stoneheart, Penny and her pig, Skahaz Shavepate, Arianne Martell, Darkstar, Victarion Greyjoy, Ser Garlan the Gallant, Aegon VI, and a myriad of other characters both great and small that viewers of the show never had the chance to meet. And yes, there will be unicorns… of a sort…
Martin also addressed the two endings debate that has recently cropped back upin the wake of this past Sunday’s finale: “Book or show, which will be the ‘real’ ending? It’s a silly question. How many children did Scarlett O’Hara have? How about this? I’ll write it. You read it. Then everyone can make up their own mind, and argue about it on the internet.”' - via COS