Actress Kelly Preston, the wife of actor John Travolta, passed away at the age of 57 on Sunday following a two-year battle with breast cancer.

John Travolta took to Instagram to confirm the death of Kelly Preston, his wife of 19 years, and also wrote a tribute honouring her two-year-long "courageous" battle with the disease.

"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," the "Grease" star wrote, adding that the "Twins" actress "fought a courageous fight with the love and support of so many."

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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. 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 Center, all the medical centers 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. All my love, JT

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The 66-year-old actor further wrote that he will "forever be grateful" to the doctors and nurses at MD Anderson Cancer Centre and all the medical centres that helped Kelly in her battle with the chronic illness. He also thanked her "many friends and loved ones who have been by her side."

A representative for the family told People magazine that the "Jerry Maguire" actress had kept her condition hidden from the public on purpose.

"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," the representative said.

Meanwhile, Travolta wrote in his tribute post that he will be taking some time to be there for their two children- 20-year-old daughter Ella, and nine-year-old son Benjamin who have lost their mother. The couple who tied the knot in 1991, welcomed three children, but their second child and first son, Jett, died at the age of 16 in January 2009.

"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.

John Travolta and Kelly Preston
Actress Kelly Preston and actor John Travolta pose at the Academy of Motion Picture Arts and Sciences' 2011 Governors Awards in Hollywood, California.

Kelly had starred with her husband in "Battlefield Earth" in 2000, and "Gotti" in 2018, which also marked her final screen credit.