HBO has officially given the go-ahead for a prequel series of 'Game Of Thrones', greenlighting a pilot episode for the series with Jane Goldman set to act as showrunner if it's ordered to series.

Per THR, the prequel series will be set thousands of years before the events of 'Game Of Thrones' and follow the origins of the White Walkers and how they came into being. The official logline reads as follows, "Only one thing is for sure: from the horrifying secrets of Westeros' history to the true origin of the White Walkers, the mysteries of the East to the Starks of legend — it's not the story we think we know."

This era, specifically referred to in the lore as the Age Of Heroes, was when the Great Houses of Westeros came into being. For example, there was Lann The Clever, a golden-haired trickster who managed to swindle Casterly Rock - who began House Lannister - and there was Bran The Builder - who began House Stark and built Winterfell and Storm's End using magic. You also had The Long Night, which was the first war between the White Walkers and the creation of the Wall to keep them out, which'll likely form a major plot point in the series.

While there hasn't been any flashback to this era in the series so far, there was one brief scene in the last season where we saw the creation of the White Walkers - but that was an indeterminate time before the Age Of Heroes, and focused on the first humans arriving on Westeros to conquer it.

As mentioned, Jane Goldman - whose screen credits include 'Kingsman', 'X-Men: First Class' and 'Kick-Ass' - has been set as showrunner and will write the teleplay with the help of George RR Martin. Obviously, given that it's early days yet, no casting has been confirmed for the series and given the nature of the plot, it's unlikely you'll see any familiar faces in it either.

Previously, HBO had announced five writers as taking a stab at successor shows to 'Game Of Thrones', with names like Brian Helgeland - who adapted 'LA Confidential' to the screen - and veterans from the series like Bryan Cogman added to the list.

At the time, HBO head-honcho Casey Bloys said that out of this bake-off situation, one would likely make it through - and it looks like this is the one.

No air date has been set as of yet, and the outcome of the pilot likely won't be known for some time - so, for now, it's a case of wait and see.