It is so common for on-screen relationships to transfer into the real world. As much as fans wanted this to happen in Grease, in a recent interview, Olivia Newton-John reveals why her and John Travolta never entered a relationship.
She described their relationship as sister and brotherly and would never see them being romantically involved after the filming.
Olivia initially passed on the role as Sandy at 28 years old. She always thought it was someone else's role. John had already been cast and said that he could not imagine anyone else to play Sandy but Olivia. So she was eventually convinced by him, and they filmed the classic film in 1977.
Olivia divulges that she was happy that they never got into a relationship, and pleased they kept it professional for filming.