The fated pairing of John Travolta and Olivia Newton-John wasn’t always a given when it came to casting the roles originated on Broadway in 1972 by Barry Bostwick and Carole Demas.

Linda Ronstadt and Marie Osmond were among the names suggested to play Sandy, Travolta recalled to Entertainment Tonight, “and I said, ‘They’re wonderful, but every guy in the world wants Olivia Newton-John as their girlfriend.’ And I knew that ’cause I felt the same way…And I said, ‘If you don’t see this, you guys are nuts.'”

Carrie Fisher, Bye Bye Birdie star Ann-Margret and The Partridge Family‘s Susan Dey were also on the list of possible Sandys.

When producer Allan Carr raised the idea of Newton-John, she didn’t immediately say yes. (But when she did, Sandy was rewritten to be Australian.)

“I was very anxious about making another film, because my music career was going well,” the “Physical” singer recalled to Vanity Fair in 2016, “and I did not want to mess it up by doing another movie that wasn’t good.”