John Joseph Travolta is an American actor, film producer, dancer, and singer. Travolta first became known in the 1970s, appearing on the television series Welcome Back, Kotter and starring in the box office successes Saturday Night Fever and Grease.
The Australian sold The Black jacket and other possessions in November, with part of the proceeds going to her cancer research centre.
But The Anonymous buyer has now handed it back to a "grateful" Newton-John.
He said: "It should not sit in a billionaire's closet for country-club bragging rights. "
The buyer was seen with his face blurred out in a video as he surprised the actor with The Jacket .
He said: "The Odds of beating a recurring cancer using the newest emerging therapies is a thousandfold greater than someone appearing out of The Blue , buying your most famous and cherished icon, and returning it to You . "Olivia Newton-John and John Travolta in Grease
It was among The Star lots in last month's auction, which raised a total of $2. 4m (£1. 8m).