We all have a memorable childhood obsession. Barbie sufficed for most little girls, and the boys I knew could cite every statistic about their favorite sports hero. But Barbie never really did it for me. I had one cherished idol who stood above all other favorite musicians, dolls, or movie stars: Olivia Newton-John.

I was introduced to Olivia the same way most people were: through Grease. Though I now hate all musicals, Grease still holds a special place in my heart. Maybe that’s because I’ve seen the movie more than 50 times (eight times in the theater when it was first released) and maybe because my mother not only allowed, but encouraged this obsession, pasting hundreds of Olivia Newton-John and John Travolta pictures all over my walk-in closet, which seemed huge (but now that I think about it, it was probably really small).

There were other favorites, yes. Around that same time, Kiss (particularly Peter Criss), captured my ghoulish imagination, as did Deborah Harry from Blondie. Though I dressed up as Peter Criss two years running for Halloween (and won both costume contests, I’m proud to say), his band didn’t resonate as loudly as Olivia. The members of Kiss were too cartoonish to be real or scary; Deborah Harry, too art-rock for my young mind to grasp.

But Olivia was real—a real-life Sandra Dee—a woman who changed from virginal teen to the quintessential Bad Girl all in the course of two hours. Probably terrified by the prospect of their 5-year-old glamming it up like Kiss and too weirded-out to support the trippy Deborah Harry, my parents happily abetted my Olivia Newton-John devotion. To them, she was the least-harmful role model: a squeaky clean Australian pop singer who sang songs like “Have You Ever Been Mellow?” How could they argue?

What they didn’t know, but what I—and nearly every other little girl in America—knew, is that we valued Olivia (and Sandra Dee) not because she was squeaky clean, but because she washed that perfect image right out of her hair. More than any other moment in Grease, we waited for that scene—the one where Sandra appears at the end-of-the-year school carnival transformed from girl to woman.

In my long and hard search to replicate the outfit (gold hoop earrings with ridges, shoulderless black top, tight and shiny black satin pants, and red Candies high heels), I discovered that many women not only remembered that scene, but reveled in it. There was no need to describe the outfit: Like me, they knew it by heart.

Why Olivia Newton-John? And why, out of all the characters in Grease, did legions of women and men latch onto Sandra Dee? Rizzo was the true Bad Girl; Sandra Dee for all intents and purposes, a poser. She didn’t even know how to put out her cigarette.

For me, the obsession went beyond Grease, it carried over to Xanadu, which had not just one, but four transformations—four totally awesome costume changes. (Though this time, I only vaguely remember the ending, when she come out with long ponytails in a terrible leopard outfit.) So enthralled was I with Olivia, I watched Xanadu at least 10 times (and it wasn’t even a good movie).

When Olivia released her magnum opus (OK, so it wasn’t that good), Physical, and scored her first really big hit, “Physical,” I was so shocked and intrigued by her new short hairdo that—after much contemplation and comparisons in the bathroom with me holding back my long, thick, curly hair in a close approximation—I decided to chop it all off to be more like Her. This from a girl who would run shrieking out of the beauty salon at the mere sight of scissors.

Somewhere along the way, I lost the gripping Olivia interest I had as a child. Other favorites—Duran Duran, Bon Jovi, Guns N’ Roses (please, stop laughing)—held court instead. But even today, when I see a Grease poster or hear a song from the movie, I can’t help but wish my way into Olivia’s red Candies while I squish out a cigarette with a sneer and say, “Tell me about it. Stud.”