The real-life disorder that inspired Joaquin Phoenix's ‘Joker’ laugh

Joaquin Phoenix has opened up about his work as the Joker in Todd Phillips’ upcoming origin story for the iconic comic-book villain, revealing the real-life condition that inspired Arthur Fleck’s laugh.

The Oscar-nominated actor told Italian publication Il Vernerdi, via Digital Spy, that he looked at the rare condition known as Pathological laughter and crying, which sees individuals either weep or laugh uncontrollably, when he started his preparation for the Joker.

Read more: New 'Joker' movie will be 'R-rated', confirms director Todd Phillips

“I started [with the laugh],” Phoenix explained. “I watched videos of people suffering from pathological laughter, a neurological disorder that makes individuals laugh uncontrollably.”

The trailers for Joker have already given audiences a sneak peak at how Fleck’s laughter evolves, as it starts out as a giggle before expanding into a loud, hysterical and immediately unsettling laugh.

The real-life disorder usually afflicts people that suffer from multiple sclerosis, Parkinson’s, or individuals that have had a stroke or had a traumatic brain injury.

This is yet further proof of the grounded nature that Phoenix and Todd Phillips have taken with the character, with the director admitting to Empire last month that they avoided the comic-books while developing the film.

Read More: New 'Joker' movie described as ‘darker than 'The Dark Knight’

"We didn’t follow anything from the comic-books, which people are gonna be mad about. We just wrote our own version of where a guy like Joker might come from. That’s what was interesting to me. We’re not even doing Joker, but the story of becoming Joker. It’s about this man.”

Joaquin Phenix will be joined by Robert DeNiro, Zazie Beetz, Frances Conroy, Brian Tyree Henry and Marcon Maron in Joker, which has been produced by Bradley Cooper and Martin Scorsese.

We’ll see what they all achieve with their take on the character when Joker is released on October 4.