Game of Thrones fans can expect another huge battle on the upcoming fourth season, but this one will be unlike any battle that has been featured before on the HBO series.

Cat Taylor, assistant to showrunners David Benioff and D.B. Weiss, recently published a new post in the Making of Game of Thrones Official Production Diary, revealing details of a new battle.

According to Taylor, "planning of this battle has been taking place for months," and director Neil Marshall is filming the episode in a "concentrated burst," unlike any other episode of season 4. Taylor said that most of the actors' work was complete before filming of this episode even began.

"Although this battle will not be laden with wildfire, I can say you've never seen an army like this on Game of Thrones," Taylor said of the epic battle.

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As for which battle from the A Song of Ice and Fire books Game of Thrones will be adapting, there are a few theories. One is that this is the battle at the Wall, in which the Night's Watch faces off against Mance Rayder (Ciaran Hinds) and his army of wildlings.

It is also possible that the battle involves the Greyjoys. It seems likely that the new character Euron Greyjoy will be introduced in season 4, brother to Balon (Patrick Malahide) and uncle to Theon (Alfie Allen) and Yara (Gemma Whelan). In the books, Euron commands his army to attack the Shield Islands in the Reach.

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Game of Thrones season 4 premieres in spring 2014 on HBO, though the network has not yet announced a specific premiere date.