Ron Howard, who starred with Cindy Williams in the 1973 film “American Graffiti,” said his former co-star had “big sister energy.”

In an interview PEOPLE, Howard remembered the “Laverne & Shirley” star, who died Wednesday.

“I’m shocked because I hadn’t seen her for years and years,” Howard told PEOPLE. “We connected at an event in Palm Springs (California) last year, and I was just so taken by how her intelligence, energy, and sense of humor…was still in high gear. And so it’s really a shock to imagine that spark is gone.”

Howard remembered his time with Williams on the set of their iconic movie.

“In American Graffiti, she was 24 and I was 18, and I had my first kissing scenes with her, but they weren’t very romantic because she knew that she had this nervous kid on her hands and she had to take charge of the situation,” he said.

“And so she was like, ‘Here’s how we got to kiss for the camera. Here’s what we have to do.’ She’s always had almost a big sister energy around me.”

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.

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.

Mark Heim is a reporter for The Alabama Media Group. Follow him on Twitter @Mark_Heim.