Laverne & Shirley's Cindy Williams Speaks Out After 'Good Friend' Penny Marshall's Death

Cindy Williams is mourning the loss of her former Laverne & Shirley costar and dear friend, Penny Marshall.

“What an extraordinary loss. My good friend, Penny Marshall is gone — one in a million,” Williams, 71, said in a statement obtained by PEOPLE on Wednesday.

“Utterly unique, a truly great talent,” Williams said of Marshall, who diedof complications from diabetes Monday night at her Hollywood Hills home. She was 75.

Williams shared, “And, oh what fun we had! Can’t describe how I‘ll miss her.”

Williams tweeted the iconic “L” that Marshall’s Laverne would wear on the show, writing, “I Love You, Partner.”

Decades before Marshall’s death, the duo starred on the beloved sitcom Laverne & Shirley for eight seasons from 1976 to 1983 as characters Laverne DeFazio and Shirley Feeney.

But seasons into filming, Williams abruptly exited the series — which left Marshall searching for answers.

“It was all insanity,” Marshall told the Archive of American Television in 2016 of Williams’ sudden exit from the show. “I was going out in front of the audience and they said, ‘What happened with Cindy?’ It was a drag. She said they didn’t want her back. There was all this garbage that was said, but no, it was [her husband]… I missed her not being there.”

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Williams, who became pregnant with her first child with her husband at the time, Bill Hudson, told the Today show in 2015 that the departure had precedence.

“I had recently gotten married and I was pregnant and I thought I was going to come back and they’d hide me behind benches, couches, pillows, and that wasn’t it,” she said. “When it came time for me to sign my contract for that season, they had me working on my due date to have my baby and I said, ‘I can’t sign this,’ and it went back and forth and back and forth and it just never got worked out.”

RELATED: Tom Hanks, Geena Davis and the Cast of A League of Their Own Remember Director Penny Marshall

While there was momentary strife in their friendship, the duo was quick to overcome their differences.

“It’s like an Italian family at a dinner table on Sunday and somebody doesn’t pass the celery properly,” Williams told Entertainment Tonight in 2015. “There’s always going to be arguments.”

And in the end, they all had one goal in mind.

“It was a show about happiness and, in the end, that was everyone’s goal,” said Williams. She added, “I go to Penny’s house I get in bed with her and we watch TV. She’s like my sister.”