The celebrity cameos were not written in the script. Robert Altman added them all in. No scripted dialogue was given to any celebrity with a cameo.
According to a contemporary article in the New York Times, director Altman convinced the celebrities who provided cameos for the film to donate their union-scale salary for one day of work to the Motion Picture and Television Country House and Hospital for retired filmmakers.
The writer pitching The Graduate: Part II to Griffin Mill is a cameo by Buck Henry (as himself). Buck Henry co-wrote the screenplay for El graduado (1967).
The roughly eight-minute opening uncut tracking shot was planned with models before production began. The area of the studio lot used was repaved so the camera dolly would move smoothly. Director Altman rehearsed the scene with the cast and crew the day before shooting began. Fifteen takes of the scene were done and the tenth take was used in the film.
Screenwriter Michael Tolkin had a film company ring him up and try to option Habeas Corpus, the blatantly ludicrous film that is pitched within the movie.
Joe Dallesandro: Star of many Andy Warhol films, appeared as himself in a restaurant scene cut from the final print.