Olivia Newton John weighs in on crazy fan theory that Sandy was dead in Grease

What does Olivia Newton John think about the theory about her character being dead in Grease?

Olivia Newton-John has weighed in on the fan theory that her Grease character Sandy was actually dead during the movie.

Fans were sent into a frenzy last week after a conspiracy theory published on Reddit suggested Sandy drowned at the beach at the beginning of the film and the rest of the movie is actually her fantasising about what would happen if she survived.

During an appearance on The Project on Tuesday night, Newton-John was asked if she could shed some light on the outlandish theory.

Olivia Newton John thought that the fan theory that Sandy being dead on Grease was crazy. Photo / Channel Ten

"I thought it was hilarious," she told the panel. "But I thought, if that's true, we were the first zombie musical! I think we look pretty good considering!"

Host Waleed Aly probed the star further about the final scene that shows Sandy and Danny flying off into the sky - which, according to the theory, symbolises heaven.

"I wondered what it was about but I didn't question it," she admitted. "It kept people interested. That's what's amazing to me - that after all these years people are still talking about it and I think that's wonderful and very funny and who knows, maybe that was the secret!"

But according to the musical's creator, Jim Jacobs, it's certainly not the secret.

Jacobs, who wrote the book and music with Warren Casey, debunked the theory last week, saying the person who came up with the idea "must have been on acid."

"Sandy was very much alive," he said, according to People magazine.