Kelly Preston, the actress married to John Travolta, has died after a private battle with breast cancer, aged 57.

The actress, who went to school in Adelaide, had been battling against breast cancer for two years, with a family representative confirming news of her passing to People today.

"On the morning of July 12, 2020, Kelly Preston, adored wife and mother, passed away following a two-year battle with breast cancer," a statement to the publication said.

Kelly Preston has died after a private battle with breast cancer, aged 57. Photo / AP

"Choosing to keep her fight private, she had been undergoing medical treatment for some time, supported by her closest family and friends.

"She was a bright, beautiful and loving soul who cared deeply about others and who brought life to everything she touched. Her family asks for your understanding of their need for privacy at this time."

John Travolta paid tribute to his wife on Instagram shortly after, with a heartbreaking post.

"It is with a very heavy heart that I inform you that my beautiful wife Kelly has lost her two-year battle with breast cancer," he posted.

"She fought a courageous fight with the love and support of so many. My family and I will forever be grateful to her doctors and nurses at MD Anderson Cancer Centre all the medical centres that have helped, as well as her many friends and loved ones who have been by her side. Kelly's love and life will always be remembered.

"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."

Preston, who was born Kelly Kamalelehua Smith on October 13, 1962, in Hawaii, launched her career in 1985 with her first major movie role in Mischief after several minor roles in television shows, including For Love and Honor.

In the next few years, Preston starred in films such as SpaceCamp (1986), Twins (1988), Jerry Maguire (1996) and For Love of the Game (1999).

Preston's final film role was in the 2018 film Gotti in which she played Victoria Gotti, the wife of Mafia boss John Gotti, who was portrayed on screen by Travolta.

Preston is survived by husband John Travolta and their daughter Ella, 20, and son Benjamin, 9.

The couple's son Jett died at age 16 in January 2009 after suffering a seizure at the family's holiday house in the Bahamas.

"It's the worst thing that's ever happened in my life," the 64-year-old told Us Weekly last year.

"The truth is, I didn't know if I was going to make it."

A house caretaker found Jett unconscious in a bathroom after hitting his head. He was taken by ambulance to a Freeport hospital, where he was pronounced dead.

The teen, the oldest child of Travolta and his wife Kelly Preston, had a history of seizures.

In 2003, Preston told Montel Williams that when Jett was 2 years old he became very ill before being diagnosed with Kawasaki disease, a condition that can cause inflammation of the arteries.

Travolta credited the Church of Scientology for helping him cope with the family tragedy.

"The church never left our side for two years," said Travolta. "I don't know if I would have made it through without their support."

The magazine revealed that he and Preston were devout followers of Scientology.