By Nick Romano
September 22, 2018 at 05:28 PM EDT

While Joaquin Phoenix is still getting into character for director Todd Phillips’ standalone Joker movie, there’s the matter of another film about the Clown Prince of Gotham in the development stage. Screenwriters Glenn Ficarra and John Requa (Smallfoot) are working on a spinoff centered on Joker and his best gal, Harley Quinn, and apparently, it’s a mashup of Bad Santa and This Is Us.

“It is great. The whole thing starts with Harley kidnapping Dr. Phil. Played by Dr. Phil hopefully. Because her and the Joker are having problems with their relationship,” Ficarra teased to the Metro. “We had so much fun, I don’t know if we have had more fun writing a script in our career.”

Credit: Clay Enos/Warner Bros.

Keep in mind that Ficarra and Requa wrote the screenplay for Bad Santa and Bad Santa 2, and directed multiple episodes of NBC’s tearjerker.

“It was sort of like, we wrote Bad Santa a couple of years ago, and it was that sensibility mixed with our This Is Us sensibility. We kind of meshed them together,” Ficarra continued. “We were doing a relationship movie but with the sensibility of a Bad Santa, f—ed up, mentally deranged people. It was a lot of fun.”

To clarify, Requa added, “I don’t know where it is on the queue of DC movies.” And there are a lot of DC movies in the works, including Gotham City Sirens, another Harley Quinn movie, and Suicide Squad 2.

Meanwhile, Phillips’ Joker is on the books for Oct. 4, 2019.