EXCLUSIVE: 40 years after 'Laverne & Shirley' premiered, Cindy Williams spills secrets from the set


40 years after the premiere of Laverne & Shirley, Cindy Williams opens up to ET about what it was like shooting the revered show.

The 69-year-old actress sat down with ET's Nischelle Turner, shortly after guest appearing on The Odd Couple, and shared that the famous Laverne & Shirley opening sequence was an idea that Penny's brother and show co-creator, the late Garry Marshall, came up with on the spot.

"We were out on the lot at Paramount on New York street, and he said, 'Penny, teach Cindy that little dance you did on the way to school with your chums,'" Williams recalled. "And he said action and we did it once, and I didn't get it -- the up and down, 'Schlemiel! Schlimazel!' -- and so the second take I got it, and he said, 'OK that's good. We're out of here.'"

WATCH: Penny Marshall Opens Up About Late Brother Garry Marshall

On the show, which aired for eight seasons between 1976-1983, the stars played roommates that worked at a Milwaukee brewery. As a California native, Williams initially struggled with finding the right voice for the Midwestern character.

RELATED: Celebrities who died in 2016:

"If you watch those first 13 episodes, which I refuse to watch now, I got this hideous kind of New York accent that was terrible," Williams admitted. "So one day, after about 13 shows, he came down to the set and said, 'Come over here and talk with me for a minute.' He sat me down and he goes, 'It is about the accent.' I said, 'Should I lose it?' and he said, 'Yes,' so I did and that was the end. And I was so thankful for that."

The Odd Couple filmed a special tribute episode to Garry, which aired Nov. 7. In the episode, Oscar (Matthew Perry) reconnects with people from his father Walter's (Garry) life while preparing to scatter his ashes behind the candy factory his father used to own.

WATCH: 13 Careers Garry Marshall Helped Launch

Last month, Penny opened up to ET about how much Garry meant to her and how he influenced her career.

"My brother gave me a life," she said. "It's not many people who have a brother who give them a life. He gave me a life and I appreciate it and I tried to not let him down."

Garry gave Penny and Williams a huge break by casting them as Laverne DeFazio and Shirley Feeney on Happy Days in 1975. The two were such a hit that they launched their spinoff the following year.

In addition to Penny and Williams, Ron Howard, Marion Ross, Anson Williams, Don Most and Pam Dawber also guest starred on the tribute episode.