George R. R. Martin
Author Martin doing his best to look like one of his charactersReuters

Season four of Game of Thrones is just around the corner, but plans are already being discussed for a film version of the hit series.

Author George R.R. Martin spoke to The Hollywood Reporter about the future of the series, and how a feature film budget may be required to round it off.

"It all depends on how long the main series runs," he said.

"Do we run for seven years? Do we run for eight? Do we run for 10? The books get bigger and bigger. It might need a feature to tie things up, something with a feature budget, like $100 million for two hours. Those dragons get real big."

Another silver screen adaptation could also be based on Tales of Dunk and Egg, a series of prequel stories set in the Game of Thrones world. "They could be the basis for [a film]," he said. "I have written these three stories, and I have about a dozen more."

Martin's A Song of Ice and Fire series of novels have been running since 1996, with the final two books yet to be released. However it is believed that Martin's has laid out his plans for finishing the story with the TV show's lead-writers, so that they know where everything is heading.

On whether the TV series might catch up him before he can release the new books, Martin said: "I'm hopeful that I cannot let them catch up with me. The season that's about to debut covers the second half of the third book. The third book was so long that it had to be split into two. But there are two more books beyond that, A Feast For Crows and A Dance With Dragons."

There are five existing books, the last of which was published in 2011. Martin's publisher said in January that book six would "certainly" not be published in 2014.

"A Dance With Dragons is itself a book that's as big as A Storm Of Swords. So there's potentially three more seasons there, between Feast and Dance, if they split into two the way they did [with Storms]. Now, Feast and Dance take place simultaneously, so you can't do Feast and then Dance the way I did.

"You can combine them and do it chronologically. And it's my hope that they'll do it that way and then, long before they catch up with me, I'll have published The Winds Of Winter, which'll give me another couple years. It might be tight on the last book, A Dream Of Spring, as they juggernaut forward."

Game of Thrones returns to Sky Atlantic on 7 April.