A version of this story originally appears in Entertainment Weekly’s Untold Stories issue.

Olivia Newton-John dominated the Hot 100 for 10 straight weeks with her 1981 smash “Physical.”

How did it make its way to you?

OLIVIA NEWTON-JOHN, Physical video, circa 1981-82

Credit: Everett Collection

I wasn’t actually aware at the time that it was written for [Rod Stewart].

I must talk with him about it one day.

Like, did he ever hear it?

Did you have second thoughts before releasing it?

I recorded it and then suddenly thought, “Goodness, maybe I’ve gone too far!”

It was a bit raunchier than I realized.

I called Roger and said, “We’ve got to pull this song!”

He said, “It’s too late.

It’s already gone to radio and it’s running up the charts.”

Let’s make it about working out!"

Was your family as surprised as you were by the song?

My mom was a very forward-thinking woman.

She was really open, so she probably thought it was funny.

My dad may not have.

[Laughs] But they were both supportive.

The clip was released in 1981the same year MTV launched.

What was it like having your video be a part of the music-video revolution?

It was very exciting!

And we did the entire [Physical] album with videos.

I think it was the first video album, if I’m correct.

It was a lot of work.

It was like making mini-movies.

Each one had a story and different little parts.

Does any memory stick out as the funniest from the shoot?

I’ll do it in my clothes."

Of course, that made it even sexier.

This was one of the first times we saw you with that super-short hairdo.

Did you cut it specifically for this?

[We] cut my hair like that the night of the American Music Awards.

I had this wild outfit on and it was just like, “Shall we?”

I’ve always been pretty bold with my hair because it grows back.

I get excited by it, not scared by it.

Nearly 40 years later, how do you feel about the song and video?

I watch that video [now] and I wonder at my energy level.

[Laughs] I wish I could still do all that!

I’m very grateful for all the people who have written music for me.