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

[G2ThaUNiT]

DonFerrari said:
Doesn't make much sense, as GRR could have released book 6 by the time that season ended and book 7 in 2020... no reason to hold both.

Writers of the show probably didn't want to have any attention taken away from the show.