John Travolta is 'very proud' of Olivia Newton-John as she battles cancer for third time

Erin Jensen

John Travolta only has loving words for his "Grease" co-star Olivia Newton-John, whose Sandy was "hopelessly devoted" to his Danny. 

At Thursday's premiere of his new flick "The Fanatic" in Hollywood, the 65-year-old actor gushed over Newton-John, who is currently battling stage 4 breast cancer. 

"She looks incredible," Travolta told Entertainment Tonight. "She doesn't look any different than years ago."

In addition to starring in "Grease" (1978), the two reunited for "Two of a Kind" (1983).

"I'm very proud of her," Travolta told ET, "and very happy about Olivia." 

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Olivia Newton-John and John Travolta attend the

Last week, Newton-John, 70, told the outlet she was "doing great."

"I'm doing really well and I'm really healthy."

The actress/singer is battling cancer for the third time. In 1992, she was diagnosed with breast cancer. After a car accident in 2013, doctors found cancer in her shoulder. Last year, the "Physical" songstress revealed her breast cancer had spread to her back with a tumor at the base of her spine.

She opened up to ET about struggling through her battle this year, but reiterated she's feeling better. 

"It was a challenging year because I broke my sacrum and I had to learn to walk again and all these things," Newton-John said. "But I am strong and I am back and I'm feeling good and loving every minute."

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Newton-John recently opened up about not focusing on how much time doctors say she has left in an interview with "60 Minutes Australia." 

"When you're given a cancer diagnosis or a scary honest diagnosis, you're suddenly given a possibility of a time limit," she said during the interview.

She continued: "If somebody tells you, you have six months to live, very possibly you will because you believe that. So for me, psychologically, it's better not to have any idea of what they expect, or what the last person that has what you have lived, so I don't tune in."

Contributing: Hannah Yasharoff, Cydney Henderson and Charles Trepany

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This article originally appeared on USA TODAY: Olivia Newton-John makes John Travolta 'very proud' amid cancer fight