Naomi Watts has been ''binging'' episodes of 'Game of Thrones' to prepare for the prequel.

The 50-year-old star has landed a leading role in the spin-off of the popular HBO series - which is based on the 'Song of Ice and Fire' book series by George R.R. Martin - which is set to come to an end when its eighth and final season airs next year.

And whilst she is unable to reveal her character, the 'Mulholland Drive' star confessed she has been catching up on the original series.

She told 'Entertainment Tonight': ''I am late coming to it, I have to say.

''But that's how I am with lots of things in life. I am binging it right now and studying. It's very exciting.''

The show, which has yet to have been given a name, is set to take place 1,000 years before 'Game of Thrones', and is one of five current projects in the franchise that are in the works from HBO.

According to reports, Naomi will be playing ''a charismatic socialite hiding a dark secret''.

Whilst the whole prequel will ''chronicle the world's descent from the golden Age of Heroes into its darkest hour. And 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.''

Meanwhile, the ending of the main show next year was recently praised as ''beautiful'' by star Peter Dinklage, who plays Tyrion Lannister.

He said: ''There are no better writers in television than [showrunners] Dan Weiss and David Benioff. They ended it brilliantly. Better than I could have imagined and you people are in for it.

''It ends beautifully for my character whether it be tragic or not.''

Several of the cast - including Kit Harington, Emilia Clarke, Sophie Turner, and Maisie Williams - have all commented on how difficult it has been to leave the show, which began in 2011, behind.