The "Cheers" and "Veronica's Closet" actress died at 71 after a brief battle with a recently diagnosed cancer, her children True and Lillie Parker shared on the star's verified Instagram account.
"She was surrounded by her closest family and fought with great strength, leaving us with a certainty of her never-ending joy of living and whatever adventures lie ahead," they wrote. "As iconic as she was on screen, she was an even more amazing mother and grandmother."
Her "zest and passion for life ... were unparalleled and leave us inspired to live life to the fullest just as she did."
A representative for Alley confirmed she died of colon cancer to USA TODAY Tuesday.
Kirstie Alley dies at 71: 'Cheers' and 'Look Who's Talking' star battled undisclosed cancer
Travolta, Alley's longtime friend and co-star ("Look Who's Talking Now"), shared a glam pic of the actress in a strapless white dress, pearls and tousled hair.
"Kirstie was one of the most special relationships I’ve ever had," he wrote on Instagram. "I love you Kirstie. I know we will see each other again."
Her "Cheers" castmate Kelsey Grammer told USA TODAY in a statement, "I always believed grief for a public figure is a private matter, but I will say I loved her."
Alley's ex-husband, "The Hardy Boys" star Parker Stevenson, wrote that he was "so grateful for our years together, and for the two incredibly beautiful children and now grandchildren that we have" and shared a throwback photo of the couple. "You will be missed."
Jamie Lee Curtis, who starred with Alley in TV's "Scream Queens" in 2016, called her "a great comic foil" on the series and "a beautiful mama bear in her very real life."
Referencing their political differences, Curtis noted they "agreed to disagree about some things," but celebrated their "mutual respect and connection."
Ever Carradine credited Alley for helping start her career.
"She told me I was funny every single day on Veronica’s Closet, and I believed her," Carradine tweeted. "She threw the best parties and gave the parakeets as our wrap gift."
Tim Allen, who co-starred alongside Alley in 1997's "For Richer or Poorer," called her a "sweet soul."
"Sad, sad news," Allen wrote on Twitter. "Prayers for all her family."
Rhea Perlman, who starred in "Cheers," said in a statement to USA TODAY that Alley was "a unique and wonderful person and friend."
"Her joy of being was boundless," Perlman said. "We became friends almost instantly when she joined the cast of Cheers. She loved kids and my kids loved her too. We had sleepovers at her house, with treasure hunts that she created."
Perlman also starred in Alley's TV Land series "Kirstie."
Perlman recalled the "massive Halloween and Easter parties" Alley would throw and invite the "entire crew of the show, and their families. She wanted everyone to feel included." She concluded: "She loved her children deeply. I’ve never met anyone remotely like her. I feel so thankful to have known her. I’m going to miss her very, very much."
Marlee Matlin posted a photo of her and Alley laughing at the People’s Choice Awards in 1990 on Twitter and remembered her friend as "complex, energetic, animated and hilarious."
Jason Alexander, who appeared alongside Alley in her titular sitcom "Kirstie," wrote that he was "so sorry" about Alley's death.
"She was a gloriously talented & unique actress and I am delighted I was able to work at her side on occasion," Alexander wrote on Twitter. "She made me feel welcome. And she made me laugh. As she did so many others."
Fellow "Shoot to Kill" star Clancy Brown wrote: "Kirstie was beautiful in so many ways. I loved working with her. There was no one like her on earth."
"Kirstie Alley is a wonderful actor who was always kind to me; even when she went full-Trump she never unfollowed me here & she always stayed friendly," comedian John Fugelsang wrote.
John Carpenter wrote: "Kirstie Alley was a delightful actress I had the pleasure to work with on VILLAGE OF THE DAMNED. She will be missed."
Jackée Harry remembered Alley as an "undeniable talent" writing that she "brought joy to many – through the screen and with her warm, hilarious spirit."
"RIP, luv. You were one of a kind," Harry added.
"I can’t believe you’re gone," tweeted Kristin Chenoweth, who starred with her in TV Land's "Kirstie." "I will see you again someday."
And journalist Megyn Kelly remembered Alley as "a beautiful, brave, funny and beloved woman."
Contributing: Elise BrLaura Trujillo
This article originally appeared on USA TODAY: Kirstie Alley: John Travolta, Parker Stevenson, Kelsey Grammer mourn