Cindy Williams, who played Shirley opposite Penny Marshall's Laverne on the popular sitcom "Laverne & Shirley," has died, her family said Monday.

Williams died in Los Angeles at age 75 on Wednesday after a brief illness, her children, Zak and Emily Hudson, said in a statement released through family spokeswoman Liza Cranis.

"The passing of our kind, hilarious mother, Cindy Williams, has brought us insurmountable sadness that could never truly be expressed," the statement said. “Knowing and loving her has been our joy and privilege. She was one of a kind, beautiful, generous and possessed a brilliant sense of humor and a glittering spirit that everyone loved.”

Williams also starred in director George Lucas' 1973 film “American Graffiti” and director Francis Ford Coppola's “The Conversation" from 1974.

But she was by far best known for “Laverne & Shirley," the “Happy Days” spinoff that ran on ABC from 1976 to 1983 that in its prime was among the most popular shows on TV.

Williams played the straitlaced Shirley to Marshall's more libertine Laverne on the show about a pair of roommates that worked at a Milwaukee bottling factory in the 1950s and 60s.

Marshall, whose brother, Garry Marshall, co-created the series, died in 2018.

“Laverne & Shirley” was known almost as much for its opening theme as the show itself. Williams' and Marshall's chant of “schlemiel, schlimazel" as they skipped together became a cultural phenomenon and oft-invoked piece of nostalgia.