* ContractualPurity: Lisa Bonet after her controversial appearance in the movie ''Film/AngelHeart'', in which she appeared nude and had a squicky sex scene.
* TheDanza: One episode near the end of season 1 has Tony Orlando guest starring as Tony Castillo. The episode, in fact, was a PoorlyDisguisedPilot.
* DawsonCasting: With Sondra, who was supposed to be in her early twenties. Sabrina [=LeBeauf=], who played her, almost didn't get the role because she was only 10 years younger than Phylicia Rashad.
** Averted by most of the other kids. When the show started, Lisa Bonet (Denise) was 17, Malcolm-Jamal Warner (Theo) was 14, Tempestt Bledsoe (Vanessa) was 11, Keshia Knight Pulliam (Rudy) was 6 and later addition Raven-Symoné (Olivia) was 3; everyone's actual age was also their age on the show. Erika Alexander (Pam), on the other hand, was 21; Pam was supposed to be 16.
* HeyItsThatGuy: Creator/AdamSandler as one of Theo's high school buddies, Angela Bassett and Iman as patients of Cliff, Naomi Campbell as the girlfriend of one of Theo's friends, etc.
** A pre-''Series/{{Star Trek The Next Generation}}'', Gates [=McFadden=] guest starred in an episode. More specifically, she's one of the party guests in the 3rd season episode that celebrates Cliff's 50th birthday.
** Robert Culp, who appeared on [[Series/ISpy another series with Bill Cosby]], showed up in one episode.
** Cliff's best friend in the neighborhood is [[Film/ThePrincessBride Vizzini]].
** One of Rudy's friends in the episode 'Slumber Party' is AliciaKeys, and 'Cockroach' is Cole from {{Martin}}.
** [[HomeImprovement Jill Taylor]] is having her 8th child in a latter season 3 episode.
** [[{{NCIS}} Tony [=DiNozzo=]]] is one of Theo's roommates in season 6.
** Then, of course, there's a very young [[ThatsSoRaven Raven Baxter]] as Olivia.
* HeyItsThatVoice: Cliff's father was the voice of [[{{Thundercats}} Panthro]].
* OldShame: Not the show itself, but at least three of the actors did say they wonder how they ever could have liked the fashions of TheEighties that are all over the place in it.
** Tempestt Bledsoe really spoke up about this in the ''Lookback Special'' given the fact that the actors didn't have a lot of say in their wardrobe and Vanessa's hairstyles in the first half of season 5 look utterly ridiculous today.
* RealLifeRelative: Phylicia Rashad's sister Debbie Allen as a sadistic aerobics instructor.
* ThrowItIn: Bill often kept the camera rolling when his many child co-stars would make mistakes because he felt [[RuleOfFunny it was funnier that way]]. In general, there was a ''lot'' of ad-libbing that made it into the final cut of each episode. Examples include:
** Rudy's friend Peter was never supposed to be silent. The child actor froze once he was on camera and Bill took the opportunity to turn the character into the SilentBob.
** Then there was the episode where he was taking care of Sondra and Elvin's twins. They would continually look up at the obvious stage lights. Bill played off on it as if the babies kept staring into space. One of the babies spit-up in the very same episode but Bill cleaned the baby up and kept going.
** One episode was to just show Cliff making a meal, and Cosby turned it into an extended bit lampooning Julia Child.
** Early seasons had Rudy forgetting her lines, so Bill Cosby just spoke them for her and kept going.
** One actor continually rendered "Doctor Huxtable" as "Dostor Husstable". It simply became a trait of his character.
* WhatCouldHaveBeen: Theo was actually supposed to be the main character of the show. The show, past the pilot, ended up being reworked into being about the entire Cosby family. By the end of the series though, [[CharacterDevelopment Theo still arguably got the most development]] of the five kids, and the series BookEnds with his graduation from college.
** Creator/WhitneyHouston auditioned for the role of Sondra.
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