Guillermo del Toro's 'Nightmare Alley' hits cinemas this weekend. It packs quite a cast between Bradley Cooper, Cate Blanchett, Toni Collette, Willem Dafoe, Richard Jenkins, Rooney Mara, Ron Perlman, and David Strathairn.

Bradley Cooper has top billing for the psychological thriller. He plays Stanton Carlisle, an ambitious and manipulative carny who meets his match with a psychiatrist , Dr. Lilith Ritter (Blanchett).

At one point in the movie, Zeena the Seer (played by Toni Collette) has a sexual encounter with Stanton.

Speaking on 'The Business with Kim Masters' podcast, Bradley Cooper describes: "I remember reading the script and thinking, he's a pickled punk in that bathtub and it's to story. You have to do it.

"I can still remember that day just to be naked in front of the crew for six hours, and it was Toni Collette's first day. It was just like, 'Whoa.' It was pretty heavy."

It was the first time Bradley Cooper has done full frontal nudity in a film.

He admitted it was "a big deal" but added that he didn't hesitate as "there was nothing gratuitous about it. It was to story."

The 'A Star is Born' star and director also notes: "Because the content of what the movie is, what we were exploring, in order to do it in a real way, it demanded that we’d be naked emotionally and soulfully."

'Nightmare Alley' is showing in Irish cinemas from Friday, 21 January.