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

[CladInShadows]

Naum said:
If this is true it's one of the biggest F**k YOU! to us book readers that made it possible to create the GoT series.

Yep.  I'm pretty soured on the whole Song of Ice and Fire situation, so if this were true, it certainly wouldn't be pushing me towards buying them.