UPDATED: G.R.R. Martin denies rumor he already finished the books but made deal with showrunners not to publish until end of show

[ptofhearts]

Never thought about it but to me it seems very likely. Maybe it was in their agreement that the show wouldn't rely completely on the books so they could have different outcomes, maybe so that the show ending wouldn't affect book sales since people would already know what happens, and vice-versa.