Cybill Shepherd and Bruce Willis did not get along during the series. Their relationship was further strained due to Willis' success with Die Hard (1988). While Willis became a major film star, he bristled at being the second-billed actor on a TV series. He also resented Shepherd whom he felt caused many of the delays in shooting.
Bruce Willis made the film Die Hard (1988) while starring in "Moonlighting." By the time the series ended, "Die Hard" was available on VHS. In one of the last "Moonlighting" episodes, Willis and a love interest are seen walking past a video rental store while an employee is tearing a "Die Hard" poster down from the window.
One of the hallmarks of this show was the irreverent (and frequent) way in which the so-called "fourth wall" was broken: at various times the actors would look directly into the camera and speak to the audience; dialogue referred to the "producers", "director" and especially the "writers" and/or "script"; and in the second-season finale episode "Camille", the characters actually left the set and went running around the film studio lot, then the episode ended abruptly around the actors when filming wrapped for the summer break (shown on-screen).
Episodes took 12 to 14 days shoot, much longer than the usual 7 days for an hour-long series. Dialogue was often written only hours before shooting. Scenes were sometimes filmed only days before airing. Because of the delays, the series never reached the usual 26 episodes per season. Only 66 episodes were produced from 1985-89.
At an average of $1.6 million an episode, this was the most expensive TV series at the time. The season 2 episode "The Dream Sequence Always Rings Twice" cost $2 million to produce. ABC was willing spend the money because the network owned the show which resulted in a much higher profit than a series owned by a separate production company.
Many episode contain a shot of Maddie's feet stepping off of the elevator and walking to her office. Glenn Gordon Caron admitted that these shots only existed to give him time to complete the script. Episodes would often begin shooting without a completed script and were constantly being rewritten. Caron would continue writing while the shots of Maddie's feet were being set up and filmed.
Because of the trademark conversations/arguments on this show (mostly, but not always, between David and Maddie), in which two or more characters are talking at length simultaneously, the scripts for this show were typically two to three times the length of a script for a similar hour-long drama.
The third season became notorious for repeated delays of new episodes, as well as an excessive number of "filler" episodes (e.g. a Christmas story, a retrospective show, a Shakespeare spoof, and an episode focused on Miss DiPesto) that ignored the primary story arc. Much of this was due to scheduling because Bruce Willis had broken his shoulder skiing, and Cybill Shepherd was pregnant with twins. One episode opener during this period mentions these problems in a mock newsreel style.
ABC and Cybill Shepherd originally wanted Harley Venton for the role of David Addison Jr., but show creator and writer, Glenn Gordon Caron, rejected him for the then-unknown Bruce Willis (both screen test were filmed - two scenes each with actress Mary-Margaret Humes playing Maddie Hayes - on 7 September 1984.) Venton's screen test, along with Willis's, appears at the end of the pilot episode DVD release.
Voice actor and stand-up comedian Maurice LaMarche auditioned for the role of David Addison. and came close to getting the part. He got three callbacks, but was eliminated before the screen-test phase.