Premise: Laverne & Shirley is an American sitcom that ran on ABC from January 27, 1976, to May 10, 1983. It starred Penny Marshall as Laverne DeFazio and Cindy Williams as Shirley Feeney, single roommates who work as bottlecappers in a fictitious Milwaukee brewery called Shotz Brewery. Among others, the series was known for Marshall and Williams' physical comedy.
Hypothesis: Penny Marshall knew Cindy Williams in real life