Bradley Cooper says filming full-frontal nude scenes in 'Nightmare Alley' was "pretty heavy".

The 47-year-old actor stars in Guillermo Del Toro's as an ambitious carnival worker and explained how he had to get his kit off on camera in an intimate scene with Toni Collette's character in a bathtub.

Bradley told 'The Business': "I remember reading in 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."

Bradley had no qualms about appearing in the nude during the making of the movie as he felt it was "demanded" to make the project a success.

The 'A Star Is Born' actor said: "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."

Bradley also explained the process of delving deep to give the best possible performance in the flick.

He said: "It really is akin to putting on a miner's kit, hat and flashlight, and looking at each other and then going down in the tunnel, knowing that you may be excavating a route that won't ever get you to the end that day but you come back up and go down again the next day."

The 'Hangover' star previously explained that it was a "unique experience" making the film amid the coronavirus crisis.

Bradley said last year: "We have been making ‘Nightmare Alley’ for the last two and a half years.

"It was a unique experience, going through the pandemic, taking six months off and revisiting it. We not only became lifelong friends, but it was an artistic experience."