George RR Martin has rebuffed the rumour that he has secretly finished the final two books in his Song of Ice and Fire series, after a Game of Thrones actor made the claim last month.

Speculation began spreading online after actor Ian McElhinney, who played Ser Barristan Selmy in the HBO adaptation, made the claim on 29 April at a fan convention in Russia. “George has already written books six and seven … but he struck an agreement with David and Dan, the showrunners, that he would not publish the final two books until the series has completed,” he told the audience at EPIC Con 2019.

The fifth novel in Martin’s bestselling series, A Dance with Dragons, was published in 2011.

But writing on his website on Monday, Martin said McElhinney’s claim was not true. “No, The Winds of Winter and A Dream of Spring are not finished. Dream is not even begun; I am not going to start writing volume seven until I finish volume six,” wrote the author.

“It seems absurd to me that I need to state this … Why would I sit for years on completed novels? Why would my publishers – not just here in the US, but all around the world – ever consent to this? They make millions and millions of dollars every time a new Ice & Fire book comes out, as do I. Delaying makes no sense.”

HBO did not ask him to delay the books, the author added, nor did the show’s co-creators, David Benioff and DB Weiss. “There is no ‘deal’ to hold back on the books. I assure you, HBO and David & Dan would both have been thrilled and delighted if The Winds of Winter had been delivered and published four or five years ago,” he wrote. “And NO ONE would have been more delighted than me.”

Martin also took the opportunity to double down on his claim that Gandalf would “kick Dumbledore’s ass”, after making the assertion at the premiere of the new JRR Tolkien biopic last week.

“Gandalf COULD kick Dumbledore’s ass. I mean, duh. He’s a Maia, folks. Next best thing to a demigod,” wrote Martin, diving deep into Silmarillion levels of Tolkien knowledge with his “maia” reference. According to the Tolkien Gateway: “The Maiar (singular Maia) were those spirits which descended to Arda to help the Valar shape the World.”

Martin wrote: “Gandalf dies and come back. Dumbledore dies and stays dead. But if it will calm down all the Potterites out there, let me say that Gandalf could kick Melisandre’s ass, too.”