HBO's hit drama "Game of Thrones" came to an end after eight seasons earlier this spring, much to the dismay of many diehard fans around the globe. But the man whose work inspired it all — author George R.R. Martin — didn't seem too upset by the show's conclusion.

Martin, who penned the series on which "Thrones" was based, told "The Guardian" the stress of finishing his next book to "stay ahead" of the show was "enormous."

"There were a couple of years where, if I could have finished the book, I could have stayed ahead of the show for another couple of years and the stress was enormous," said the writer. Martin released the fifth book in the fantasy series in 2011, as the drama was just hitting viewers' TV screens.

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He told "60 Minutes" in April he was initially "completely confident," that he could churn out the last two books in the series — "Winds of Winter" and "A Dream of Spring" — before the show needed new material. As Martin explained to the "The Guardian," the pressure to complete the novels so quickly just wasn't conducive to his working style.

"I don't think it was very good for me because the very thing that should have speeded me up actually slowed me down," Martin told the outlet. "Every day, I sat down to write and even if I had a good day — and a good day for me is three or four pages — I'd feel terrible because I'd be thinking: 'My God, I have to finish the book. I've only written four pages when I should have written 40.'"

The fifth season of the series largely reached the end of the source material in Martin's last-written book, "A Dance with Dragons." And the final three seasons of the hit went on without the author's new text. He wasn't totally removed from the creative process.

Martin told "60 Minutes" he held "several days of story conferences" at his home to get the showrunners up to speed, but added there was "no way to get in all the detail."

While Martin explained to "The Guardian" that the show "completely changed" his life, he didn't seem totally distraught over its finale. "Having the show finish is freeing, because I'm at my own pace now," said the author. "I have good days and I have bad days and the stress is far less, although it's still there ... I'm sure that when I finish 'A Dream of Spring' you'll have to tether me to the Earth."

Martin told "60 Minutes" that while the show moved on without his work, he didn't think the conclusion of his books would be "that different," but told "The Guardian" the series' ending wouldn't impact his own.

Martin seemed to have set himself a deadline for the series' next book on his Not A Blog website in May, while responding to a video from Air New Zealand offering him a free trip to that country so he can finish the work, reports CNET.

Explaining that he is traveling to New Zealand in the summer of 2020 for the World Science Fiction Convention, Martin wrote, "If I don't have 'The Winds of Winter' in hand when I arrive in New Zealand for Worldcon, you have here my formal written permission to imprison me in a small cabin on White Island, overlooking that lake of sulfuric acid, until I'm done. Just so long as the acrid fumes do not screw up my old DOS word processor, I'll be fine."