There's now a fifth Game of Thrones 'spin-off' show in the works

"We had four scripts in development when I arrived in LA last week, but by the time I left we had five," writes Martin on his blog. "We have added a fifth writer to the original four."

As for who that fifth writer might be, well it's a man, and he clearly knows Westeros pretty well, but beyond that Martin is remaining tight-lipped. "No, I will not reveal the name here. HBO announced the names of the first four [writers], and will no doubt announce the fifth as well, once his deal has closed. He's a really terrific addition, however, a great guy and a fine writer, and aside from me and maybe [Game of Thrones contributors] Elio [Garcia] and Linda [Antonsson], I don't know anyone who knows and loves Westeros as well as he does."

Whoever it is he will join Kick-Ass co-writer Jane Goldman, Man Men writer Carly Wray, LA confidential scribe Brian Helgeland, and Kong: Skull Island's Max Borenstein in working with Martin on one of the five separate... projects.

We are choosing our words carefully here as Martin is adamant that the ideas – which are unlikely to all go beyond the script stage – are not Game of Thrones spin-offs.

"For what it's worth, I don't especially like the term 'spinoff,'" writes Martin, "and I don't think it really applies to these new projects. What we're talking about are new stories set in the 'secondary universe' (to borrow Tolkien's term) of Westeros and the world beyond... one with thousands of years of recorded history.

"None of these new shows will be 'spinning off' from GOT in the traditional sense. We are not talking Joey or AfterMASH or even Frazier or Lou Grant, where characters from one show continue on to another. So all of you who were hoping for the further adventures of Hot Pie are doomed to disappointment."

Ok, shame, but what are they about then? Well, in chronological terms they are all apparently prequels rather than sequels but they don't cover the events of the Tales of Dunk and Egg novellas or Robert's Rebellion, which led to the Baratheon king being ensconced on the Iron Throne and has been the subject of a petition from those who are desperate to see it dramatised.

That would be pointless, says Martin: "By the time I finish writing A Song of Ice & Fire" – insert bitter laughter here – "you will know every important thing that happened in Robert's Rebellion. There would be no surprises or revelations left in such a show, just the acting out of conflicts whose resolutions you already know. That's not a story I want to tell just now; it would feel too much like a twice-told tale."

But if he won't tell us what the pilots are about, rest assured that Martin is involved in all of them and has been spending plenty of time with each of the writers both discussing ideas and drinking.

"Every one of the four has visited me here in Santa Fe, some of them more than once, and we've spent days together discussing their ideas, the history of Westeros and the world beyond, and sundry details found only in The World of Ice & Fire and The Lands of Ice & Fire... when we weren't drinking margaritas and eating chile rellenos."

Next question: how do we get a piece of that action?

Game of Thrones season 7 comes to Sky Atlantic and NOW TV on 17th July, simulcasting each week with the US at 2am and repeating at 9pm the same day