"I always feel she is with me," John Travolta told PEOPLE in 1977, months after girlfriend Diana Hyland had died from breast cancer at age 41

Decades before losing wife Kelly Preston to breast cancer, John Travolta mourned his girlfriend Diana Hyland, who died of the same disease.

On Sunday, Preston died at age 57 following a secret two-year battle with breast cancer. "She fought a courageous fight with the love and support of so many," Travolta, 66, shared on Instagram, adding that her "love and life will always be remembered."

More than 40 years ago, the Pulp Fiction actor lost his girlfriend at the time, Hyland, to breast cancer in 1977 when she was 41 and he was 23.

Hyland was an actress known for roles in Burke's Law (1965) and Smoky (1966), and for starring alongside Travolta as his mother in 1976's The Boy in the Plastic Bubble. She had had a mastectomy two years before her death, Travolta told PEOPLE in June 1977, adding that Hyland "didn’t know she was going to die for sure until two weeks before."

"And when I first knew her, there was a possibility it would never happen," he said at the time.

In the middle of production on Saturday Night Fever, Travolta flew home to Los Angeles when Hyland's health declined dramatically. He said he was with her when she died, recalling that he "felt the breath go out of her."

"I gave her great joy the last months of her life," he said. "I always feel she is with me — I mean, her intentions are. Diana always wanted the world for me in every possible way."

John Travolta and Diana Hyland
Diana Hyland and John Travolta in December 1976
| Credit: Frank Edwards/Fotos International/Getty

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Mourning Hyland in 1977, the actor said he had "never been more in love with anyone in my life."

"I thought I was in love before, but I wasn’t," said Travolta at the time. "From the moment I met her I was attracted. We were like two maniacs talking all the time on the set of Bubble. After a month it became romantic."

"I had more fun with Diana than I ever had in my life," he said. "And the odd thing is just before we met I thought I would never have a successful relationship. She told me that she too had thought the same thing. Then, bam."

John Travolta and Diana Hyland sighting in LA
Credit: Tom Wargacki/WireImage

Travolta wouldn't meet Preston until screen testing with her for their 1989 comedy The Experts. When Travolta and Preston married on Sept. 5, 1991, Preston was two months pregnant with their son Jett.

Along with Travolta, Preston is survived by the couple's children: daughter Ella, 20, and 9-year-old son Benjamin. Son Jett died at age 16 in January 2009. In his emotional tribute to his late wife, Travolta wrote that he had a "very heavy heart."

"My family and I will forever be grateful to her doctors and nurses at MD Anderson Cancer Center, all the medical centers that have helped, as well as her many friends and loved ones who have been by her side," the actor wrote.

"... I will be taking some time to be there for my children who have lost their mother, so forgive me in advance if you don't hear from us for a while. But please know that I will feel your outpouring of love in the weeks and months ahead as we heal," he concluded.