A Song of Ice and Fire author George R.R. Martin gave an update on his progress on the sixth book in the series, The Winds of Winter, saying “It’ll be done when it’s done. It’s been going very well lately, so, knock
wood.”
This update comes from a red carpet interview with Entertainment Tonight (via Gamespot) for the Season 8 premiere of Game of Thrones, where Martin also divulged which storyline he wished made it from the books to the show. “Lady Stoneheart,” he said confidently. “Certainly the book I’m writing now it’s an important thread.”
Source: IGN.com Winds of Winter: George R.R. Martin Says It's 'Going Very Well Lately'