Guillermo del Toro's Nightmare Alley will be rated 'double R'

Guillermo del Toro's 'Nightmare Alley' is "a straight, really dark story."

The acclaimed director insists his forthcoming adaptation of William Lindsay Gresham's 1947 novel of the same name will have a "big" R-rating and revealed that his re-imagining of the story won't focus on the entire novel and instead will revolve around "elements that are darker in the book".

Speaking to Collider, he said: "Well what it is, is that book was given to me in 1992 by Ron Perlman before I saw the Tyrone Power movie, and I loved the book.

"My adaptation that I've done with [co-writer] Kim Morgan is not necessarily--the entire book is impossible, it's a saga.

"But there are elements that are darker in the book, and it's the first chance I have-in my short films I wanted to do noir.

"It was horror and noir. And now is the first chance I have to do a real underbelly of society type of movie. [There are] no supernatural elements. Just a straight, really dark story."

When asked whether the movie would be rated R, he replied: "Big R. Double R!"

'Nightmare Alley' follows Stanton 'Stan' Carlisle, a man who joins a travelling carnival where he attempts to learn the ways of mind-reading act Mademoiselle Zeena and her alcoholic husband, Pete.

Following Pete's death, Zeena takes on Stan as a stage-partner where he proves more successful than her late husband and soon graduates to full-blown spiritualist, catering to the needs of the rich and gullible in their well-upholstered homes.

The movie already boasts an all-star cast which includes Bradley Cooper, Cate Blanchett and Willem Dafoe.