Game of Thrones prequel's full main cast revealed

Eight rising stars have been cast in main roles, set to star alongside Naomi Watts, who was previously announced as a series lead.

What roles each new actor is playing is being kept under wraps, but a little more about the plot has also been teased.

"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," HBO says in a logline.