John C. Reilly and Daniel Day-Lewis can be seen in the background wandering around during a Brad Pitt scene.
Roger Ebert's scene took over 45 minutes to shoot. Roger Ebert recited the "White Parasol" monologue from Citizen Kane (1941) four times so that Ryan R. Williams could get the proper coverage.
The title, "Abby Singer," references an often-used expression in Hollywood production, named after an assistant director (later a Production Manager and MTM Production Executive) Abby Singer who, when asked if the upcoming shot would be the last, famously would announce "this is the next-to-the-last shot for the day." The final shot of the day is traditionally referred to as "the martini."
The infamous "helicopter" shot was actually taken from a ski-lift during the middle of summer.
There was no script used during any part of the filming.