Preston's husband, John Travolta, mourned her death on Instagram. "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," he wrote.
"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," he continued. "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."
Stars quickly took to social media to pay tribute to Preston and express their condolences to her family. In addition to Travolta, the actress is survived by 20-year-old daughter Ella and 9-year-old son Benjamin. The couple's son, Jett, died at age 16 in 2009.
Preston and Travolta's longtime friend, Kirstie Alley, tweeted a sweet message along with the song, "Somewhere Over the Rainbow." She wrote, "Kelly...you are Hawaii and I am Kansas. The perfect combination for best friends. I love you forever Shooster...so here’s to 'until we meet again somewhere.'"
Preston's Twins co-star, Arnold Schwarzenegger, tweeted, "Kelly Preston was extraordinary. I was lucky enough to star with her and direct her, and her talent was off the charts. She had such a big heart, she was a wonderful wife and mother, and my thoughts are with John and the whole family."
Her other Twins, co-star, Danny DeVito, also posted, "Thinking of her, always the sweetest brightest energy, and John and their wonder family....much love."
Tim Allen, who costarred in Wild Hogs with Travolta, sent his love to the actor on Twitter. "So sad for my pal Travolta," the actor wrote. "So hurt for his families loss. Kelly is a gem of so many facets. My families prayers and love to you and the family JT."
Barbra Streisand honored her "wonderful friend" with a sweet throwback photo on Instagram. The two pals made headlines in 2015 with a star-studded pic showing them hanging out with Travolta, Streisand's husband, James Brolin, Lady Gaga and Ryan Murphy.
"Kelly Preston was a wonderful friend…one of the loveliest people in our lives and such a great mother and wife," Streisand captioned her post. "Our hearts are forever with John, Ella, and Ben. Jim and I are heartbroken."
Meanwhile, Schwarzenegger's ex-wife, Maria Shriver, wrote, "Shocked by this sad news. Kelly was such a bright loving soul, a talented actress, and a loving mom and wife. My heart breaks for her family who have already known such sadness and grief. Join me in sending them love and strength. #RIP #KellyPreston."
Reese Witherspoon tweeted, "Deeply heartbroken for the whole Travolta family over the passing of the wonderful, kind, and extremely talented Kelly Preston. 💔I’m sending love and prayers to her husband, her children and everyone who loved her. May She Rest In Peace. 🙏🏻"
"💔💔💔💔💔 love you so," Sarah Paulson commented on Travolta's Instagram.
"I’m in absolute shock," Josh Gad wrote on Twitter." What a beautiful and amazing actress and person. So sad to hear of her passing at such a young age. My heart goes out to John Travolta and the entire family. What a loss. RIP #KellyPreston."
"A beautiful lady. Inside and out. A crushing loss. Rest In Peace, Kelly Preston," Holly Robinson Peete wrote.
"I was lucky enough to work with her on one of my very first films, For Love of The Game," Daniel Dae Kim tweeted. "We were shooting on cold days in Colorado, but she couldn’t have been warmer or kinder to a young, nervous actor trying to make good. I’ll never forget that. Thank you Kelly. #RestInPeace."
See more reactions to Preston's death below.
People was first to report Preston's death.