"It's the best finale we've ever, done bar none," they said in a statement.
"The performances from our cast, the direction from Alex Graves, the VFX work, the new cues from Ramin Djawadi - all of it came together in perhaps the finest hour we've produced."
Indeed, the pair are so "immensely proud" of The Children that they feel "a little intimidated" at the prospect of creating episodes to better it next season.
Fans are expecting news on the fate of Tyrion Lannister after he was sentenced to death at the end of the eighth episode and, with Jon Snow on a mission to kill Mance Rayder, there is plenty of scope for violence and a ton of fake blood.
Past season finales have been quieter and calmer in tone than the penultimate episode, but The Children looks set to buck this trend.
Details of the storyline have been kept tightly under wraps, but after Lena Headey sparked calls of "Spoiler!" with an Instagram post captioned 'my stone heart' last month, some fans are expecting to catch a first glimpse of Lady Stoneheart.
The finale, due to air on Soho at 8.30pm on Monday night, will run for 66 minutes.
All will be revealed...
- Independent
The third season of Game of Thrones starts free-to-air on Prime on Tuesday at 9.30pm