Parts of Joker: Folie a Deux's script was torn up during filming and rewritten "on a napkin"

Joker: Folie a Deux is seemingly embracing the Clown Prince of Crime's skill of chaotic improvisation, with star Lady Gaga and director Todd Phillips both revealing that the DC movie often tossed out its script and started over – during filming.

"We’d very often meet in Joaquin’s trailer and sometimes we would just tear the script up and start all over," Gaga, who plays Harleen Quinzel in the sequel, told Vogue. "It was a really cool, liberating process."

Phillips added, "You think, Okay, this scene works, let’s just go shoot it. And Joaquin’s like, ‘No, no, no, let’s just have a quick meeting about it,’ and it’s three hours later and you’re rewriting it on a napkin."

Of course, the script being dramatically changed – and rewritten – partway through filming is nothing new, even in the realm of comic book movies.

Infamously, Jeff Bridges said that 2008's Iron Man (where he played Obadiah Stane) had its script thrown out on the "first day of shooting" after weeks spent working on it with Robert Downey Jr. and director Jon Favreau.

"So there was a lot of confusion about what our script was, what we were gonna say," Bridges told Vanity Fair. "We’d spend hours in one of our trailers going over lines and exploring how we were going to do it.”

Early reactions to Joker: Folie a Deux called it a "brilliant musical return to a world of madness", but critics have been less kind, with it currently sitting at a mixed 61% on Rotten Tomatoes.

In Total Film's Joker: Folie a Deux review, Jordan Farley described the movie as "an unconventional musical sequel that fails to hit the high notes."

Joker: Folie a Deux releases in cinemas on October 4. For more, check out the upcoming movie release dates we still have to look forward to in 2024.