Olivia Newton-John lost these sparklers at Studio 54 ‘Grease’ premiere party

Olivia Newton-John’s sparkling personality was reflected in the diamonds she lost one summer night in the Big Apple.

All eyes were on the “Grease” actress, who died on Monday after a 30-year battle with breast cancer, when she attended the film’s premiere party at Studio 54 on June 13, 1978, alongside co-star John Travolta.

After the film’s debut at the Ziegfeld Theatre, the stars headed to Studio.

“At the end of the night, someone got a call saying that Olivia Newton-John lost her diamond bracelet,” said Chuck Garelick, head of security at Studio from 1977 to 1984.

“When I was told it was missing, the club had already emptied out a bit. I went back in before the rest of the vultures came in, because we had some guys famous for finding stuff,” he told The Post.

“She lost it early. When she got there, she was sitting on the banquette. And I went to the banquette where they were sitting and I started rummaging around and sure enough, I found it. It was like a tennis bracelet,” Garelick recalled.

“The banquettes had silver rolls on the back of them, and it got there in between them. I didn’t see it at first, I felt it, because you couldn’t see it because it was almost the same color,” he added.

Sometime between 4:30 a.m. and 6 a.m., after the club closed, Garelick went to her hotel to return the jewelry. A man — presumably Lee Kramer, her boyfriend at the time — answered the door.

“I said, ‘I’m the director of security at Studio. I think I found Miss John’s bracelet,’” Garelick, 65, said. “And he yelled out inside, ‘Hey, they found the bracelet!’”

He was taken aback by the Australian actress’ hopelessly devoted reaction.

“All of the sudden, the door opens wide and she comes running towards me, gave me a hug, really knocks me down with big thank yous,” he explained.

“And it was just, ‘Come on in. Have a drink.’ I’m like, ‘No, no, that’s ok,’” he said. “But it was just the sweetest thing, the way she said thank you and I’ve never forgotten it.”

Art imitated life because Newton-John was about to become Hollywood’s newest sweetheart.

“She was one of those people who did connect with you when you talked to her,” gushed TV host Bill Boggs, who was a guest at Studio that night.

Those gathered there, including other A-Listers like Elton John and Andy Warhol, could all sense the electrifying vibe, he said.

“The mood was jubilant that night,” Boggs, 80, said. “Sometimes people went there because they wanted to dance, have fun, get high and they didn’t go in with a sense of joy, they were going in to get a sense of joy. That night at that party, the sense of joy was coming from the people.”

The “Grease” soundtrack spun from the legendary disco’s DJ booth, and to the crowd’s delight, Sandy took to the dance floor with her Danny.

“I do remember her and John Travolta dancing together and everybody getting excited about that,” said Brooklyn native Gerard Renny, 63, who worked security at Studio from 1977 to 1979 and is now director of operations at the Upper East Side bar Ethyl’s.

Added Boggs: “That was the highlight of the evening — it was only equal to when he danced with Princess Diana at the White House.”