Barry Bostwick Had a Relationship with Grease Costar Carole Demas — But Kept It Under Wraps!

“Opening day of rehearsals, I walk in, and I see all these people, and here comes Barry — and he looks right through me like he’s never seen me before!” Carole Demas, who played Sandy, tells PEOPLE

Barry Bostwick had a real-life Grease moment with his onstage Sandy, according to costar Carole Demas.

Demas, who originated the role of Sandy Dumbrowski in the 1972 Broadway production of Grease, tells PEOPLE at a party celebrating the release of the new book Grease, Tell Me More, Tell Me More that Bostwick — who played her Danny Zuko — blew right past her on their first day of rehearsal.

“Barry and I had a relationship going. We were close before the show began,” she says, adding that it wasn’t exactly “an exclusive thing” because “this was the ’70s, you know.”

Still, she says, “We were close enough so that we spent Christmas together at my sister’s.”

During their final audition for the roles of Danny and Sandy, the two were paired together to dance “to see how they fit,” says Demas. “I was hoping that was going to work because Barry is 6’4″, and I’m like 5’3″. He whispered in my ear, and he said, ‘Stand on my feet.’ And I thought, ‘This is going to be cute,’ so I stood on his feet, and I put my arms up around his neck and looked into his eyes, and we kind of slow danced, and I think that was the moment… I think they were very interested in the both of us, and they saw chemistry and that was that.”

The two ended up being cast as the famous Rydell High lovebirds. But, in true Grease fashion — much like when Danny pretends not to know new Rydell student Sandy, despite their summer fling — Bostwick apparently ignored Demas once they got into the rehearsal room.

“I was thrilled that we were going to be in the show together,” says Demas. “Opening day of our rehearsals, I walk in, and I see all these people, and here comes Barry — and he looks right through me like he’s never seen me before!”

During a recent interview with other cast members on the Richard Skipper Celebrates YouTube show, Bostwick apologized to Demas for his actions nearly 50 years later.

“Carole… I’m sorry that I ignored you on the first day of rehearsals. Apparently, in the book [Grease, Tell Me More, Tell Me More], I came into rehearsal, and I didn’t speak to you. And we obviously had had an affair and were having an affair at the time, apparently, and I totally ignored you. And my God, I’m so sorry for that!” he said to her via the Zoom interview.

“That’s just my social anxiety and my wanting to be in front… You are always my good girl, you are always my sweetheart. And so I apologize for ignoring you,” he added, asking her: “Did I talk to you the second day?”

When Demas shook her head no, he replied, “No?! What an a––––!”

Demas tells PEOPLE, “He apologized to me publicly. It only took 49 years!”

There seem to be no hard feelings, though. She adds, “He was so gorgeous, oh dear God!”

Bostwick, who was unable to attend the party celebrating the release of the new book that shares behind-the-scenes stories from the Broadway musical, spoke to the cast via Zoom at the party.

“I have one special Sandy in my life, and she’ll forever live in my heart, and that’s Carole Demas,” he said. “And she has always been the most famous Sandy. There’s been one other Sandy who once sang a song — not from Grease, and if it had been, Grease probably would have been a hit! — but it sums up for me, everything I feel about you, Carole.”

Referencing Olivia Newton-John’s “I Love You, I Honestly Love You,” he said, “It goes like this: I’ve got something to tell you. I love you, I honestly love you.”