Donna Mills Reveals She Was the Inspiration for Sandy in 'Grease'

Donna Mills still stuns at 81... and she's still full of surprises!

The "Knots Landing" actress and co-founder of Mandeville Vineyards has a flourishing Instagram, in part because of her ageless looks and in part because she keeps the content flowing.

On Sunday, she wowed fans with a secret as well as with two bombshell looks, first appearing as demure Sandy and then as hot Sandy from "Grease."

"Did you know that I went to school with Jim Jacobs?" she asks fans in her leather jacket. "Jim Jacobs, who wrote 'Grease.' Jim Jacobs who used me as his model for Sandy."

She goes on, "I didn't know it at the time, but I found out years later: I was the original Sandy."

Watch the startling transformation here!

Mills, who's been getting glammed of late by L.A.-based makeup artist Brett Freedman, hardly seems to have aged since her days as Abby on "Knots Landing" (1980-1993), and has worked mostly on TV ever since, including recurring on "General Hospital."

Her next big project is a role in Jordan Peele's "Nope," coming in July. She told Tamron Hall in May about the movie, her feature-film comeback, "I had to sign an NDA, I couldn't even say I was in the film for months and months and months... I can not say anything about what it's about. But it's really good!"