"A Song of Ice and Fire" author George R.R. Martin has confirmed his openness to having a "Game of Thrones" prequel. He also revealed what possible stories could be told in the spin-off.

In an interview by IGN (video below), the author revealed that he already has material for a "Game of Thrones" prequel. The "Tales of Dunk & Egg" is a series of fantasy novellas by Martin which was first published in 1998.

"I have been writing for a number of years a series of novellas set in the same world of Westeros but a hundred years earlier," he said. "[it's] about two characters called Dunk and Egg. I've published three of those novellas, 'The Hedge Knight,' 'The Sworn Sword' and 'The Mystery Knight.'"

Martin admitted that he has about nine or 10 more novellas to be released. "So we have been playing with the idea of doing those, you know, as prequels," he admitted.

"They're somewhat lighter in tone than the main series, a little more adventurous but my fans love them and I love the two characters too and it all ties to Westeros. Maybe that will be what we'll do, we'll see."

According to EW, Martin believes that the "most natural follow-up" would be the adaptation of the "Tales of Dunk & Egg." "Each of the novellas could easily be done as a two-hour stand-alone movie for television; that would probably be the ideal way to do them, rather than as an ongoing weekly series," the author told the publication.

Meanwhile, MensXP made a list of the possible "Game of Thrones" prequel cast. Sophie Cookson would be perfect for the role of Catelyn Stark, Naomi Watts could take on Rhaella Targaryen and Tywin Lannister could be portrayed by Tony Curran.

Others included in the list are Charlie Cox as Rhaegar Targaryen, Peter Capaldi as Aerys Targaryen, Imogen Poots as Cersei Lannister, Taron Egerton as Jaime Lannister, Aaron Taylor Johnson as Benjen Stark, Tom Hardy as Robert Baratheon and James McAvoy as Ned Stark.