"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 66-year-old "Grease" actor said in his post.
Born Kelly Kamalelehua Smith in Honolulu, she changed her name to Kelly Preston before securing her first film role in the 1985 romcom "Mischief," then appeared in another teen comedy, "Secret Admirer."
Travolta, star of the hit dance movies "Saturday Night Fever" and "Grease," met Preston in 1988 when they appeared together in a film called "The Experts." They married on Sept. 5, 1991, in Paris.
Preston is survived by her husband and their children - daughter Ella, 20, and 9-year-old son Benjamin. Their son Jett died at age 16 in January 2009 during a family vacation in the Bahamas."I have never met anyone as courageous, strong, beautiful and loving as you," her daughter, Ella Travolta, wrote in a tribute posted on Instagram.