Joker: Folie à Deux composer Hildur Guðnadóttir discusses how establishing the sound of the world in the first Joker movie helped them lay the groundwork for the sequel. Joaquin Phoenix will return as Arthur Fleck, aka the Joker, in the sequel, living in Arkham in the aftermath of his numerous crimes, with Lady Gaga joining as Hareen Quinzel, aka Harley Quinn. While details of the movie have been kept under wraps, it has been revealed that this will be a musical.

In an exclusive interview with Screen Rant for A Haunting In Venice, Guðnadóttir also teases her work on the upcoming Joker: Folie à Deux. She explains how the sound of this world was established in Joker, which gives her a jumping-off point for the sequel. She breaks down how the sound of this world is an integral part of the Joker character, and knowing that helped them when working on new aspects of the world like the songs in Joker: Folie à Deux. Check out Guðnadóttir's full quote below:

Hildur Guðnadóttir: Well, I think that the process was the big difference for me in the process is that we already have the sound world of the first film, we set it in the first film. I think the sound world that is in that film is so incredibly connected to that character and it's such a big part of that of the whole film. So I think the big difference is that we basically knew his sound going into this film and then so it made the process a little bit different. Not to be seeking as you're working on it, but working into a world that exists. And working from there until something new. Like the songs and all of these things. So that was quite fun.

How Joker 2 Can Build From The First Movie's Score

Although the musical element could seem like a drastic shift from the gritty tone of the first movie, that may not be the case. Foil a Deux is likely a reference to the shared delusional disorder and could be a hint of how the Joker and Harley Quinn are pulled together. With Lady Gaga playing Harley Quinn, this could point to the musical elements being completely in the pair's minds as they lose themselves in both one another and their delusion. This could also add an eerie element to the musical aspect, whether the tone is more romantic, a Broadway showstopper, or Sweeney Todd-esque.

Related: Joker 2's Biggest Challenge Was Created By Joker's Twist Ending

With Guðnadóttir winning an Academy Award for the score in Joker, it's no surprise that she's returning for the sequel. Establishing the musical signature of Arthur as well as this world as a whole helps her build out new characters like Harley Quinn as well as the musical element. How the score in Joker: Folie à Deux could be a way to show the mental and emotional journeys of each character, especially with how the transition from Harleen Quinze to Harley Quinn can be reflected.

How the original score comes into play with the lyrical musical element could be an indicator of how Arthur and Harleen are losing themselves as well. While details about the musical element of the film are being kept close to the vest, if they are in Arthur and Harleen's heads, this could be reflected by a score pulling from the first film used in moments that reflect the real world while a more bombastic Broadway style is used in their delusion. While much about this movie remains a mystery, it is exciting to know Guðnadóttir is staying true to the award-winning Joker score for Joker: Folie à Deux.