season episode "Kamp Krusty" into a film, but difficulties were encountered in expanding the episode to feature-length. For a long time, the project was held up. There was difficulty finding a story that was sufficient for a film, and the crew did not have enough time to complete such a project, as they already worked full-time on the show. Groening also expressed a wish to make Simpstasia, a parody of Fantasia; it was never produced, partly because it would have been too difficult to write a feature-length script. At another point, it was briefly suggested to do an anthology-style Treehouse of Horror film, but such suggestion was never pursued. Recurring guest performer Phil Hartman had wished to make a live-action film based on his character Troy McClure; several of the show's staff expressed a desire to help create it, and Josh Weinstein proposed to use the plot of the 1996 episode "A Fish Called Selma" for the film, but the project was canceled following Hartman's death in 1998. The project was officially green-lit by 20th Century Fox in 1997, and Groening and James L. Brooks were set to produce the film. The voice cast was signed on to do the film in 2001, and work then began on the script. The producers were initially worried that creating a film would have a negative effect on the series, as they did not have enough crew to focus their attention on both projects. As the series progressed, additional writers and animators were hired so that both the show and the film could be produced at the same time. Groening and Brooks invited Mike Scully and Al Jean (who continued to work as showrunner on the television series) to produce the film with them. They then signed series director David Silverman to direct the film. The "strongest possible" writing team was assembled, with many of the writers from the show's early seasons being chosen. David Mirkin, Mike Reiss, George Meyer, John Swartzwelder, and Jon Vitti were selected. Ian Maxtone-Graham and Matt Selman would also join later, and Brooks, Groening, Scully, and Jean also wrote parts of the script. Sam Simon did not return having left the show over creative differences in 1993. Former writer Conan O'Brien expressed interest in working with the Simpsons staff again, although he later joked that "I worry that the Simpsons-writing portion of my brain has been destroyed after