Olivia Newton-John has described Kelly Preston as a "radiant, warm and gentle spirit" and devoted wife and mother.
Newton-John delivered the emotional tribute after Preston succumbed to a two-year battle with breast cancer on Sunday.
Newton-John, who has fought her own battles with cancer, starred with Preston's husband John Travolta in Hollywood's 1978 musical Grease, and the two remained close friends over the decades.
"Kelly was a radiant, warm and gentle spirit - a loving, devoted wife, mother and sweet friend," Olivia Newton-John wrote on Twitter on Monday.
"My heart breaks for John, Ella and Ben.
"No words can express my sorrow for her family.
"Kelly's light shines on in her beautiful children."
Preston and Travolta had three children, including Ella, 20, and nine-year-old son Benjamin.
Jett, who was autistic and had seizures, died aged 16 while the family was holidaying in the Bahamas in 2009.
Preston's film career included roles in Twins, Jerry Maguire, For Love of the Game and her final role, opposite her husband, in 2018's Gotti.
"Kelly's love and life will always be remembered," Travolta wrote on Instagram.
"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."
Australian Associated Press