From People magazine: Olivia Newton-John has proudly kept the ionic sharkskin pants she rocked as Sandy in Grease, the 1978 musical-turned-movie that catapulted her and John Travolta to megastardom. But don’t ask her to put them on again. “The zipper was broken, so they had to stitch me in,” says Newton-John, now 61. “I don’t even want to try. I was pretty skinny when we shot that!”

This month fans can shimmy all over again as Grease Sing-a-Long is released in theaters. The stars share some off-camera memories. “I was 29 and worried I wouldn’t look young enough” to play a teen, says Newton-John. “But the energy and camaraderie-it was like we were kids again.”

(See the photo gallery on Travolta.com for more Grease photos!)

Read the full article and see the behind the scenes photos in People magazines- on newsstands now.