Celebrities and former co-stars are paying tribute to Kirstie Alley following her death.

On Monday (Dec. 5), Alley's official Twitter account announced the star's passing. She died from cancer.

One of the first celebrities who honored the actress was her former Look Who's Talking co-star, John Travolta. The pair starred together in the 1989 comedy as well as its 1990 sequel, Look Who's Talking Too, and 1993's Look Who's Talking Now.

"Kirstie was one of the most special relationships I’ve ever had. I love you Kirstie. I know we will see each other again," Travolta wrote, sharing two photos of his co-star.

"I'm sorry buddy, I know you loved her," Motley Crue drummer John-5 commented under Travolta's post.

Jamie Lee Curtis, who co-starred with Alley on Scream Queens, shared a moving tribute to the 71-year-old on Instagram.

"I've just heard the sad news that Kirstie Alley has died. She was a great comic foil in @tvscreamqueens and a beautiful mama bear in her very real life. She helped me buy onesies for my family that year for Christmas. We agreed to disagree about some things but had a mutual respect and connection. Sad news," Curtis wrote.

On social media, Larry the Cable Guy called Alley "a sweetheart," while Valerie Bertinelli wrote, "Oh Kirstie ... Rest in Peace."

In her death announcement, Alley's family revealed the actress passed away suddenly from cancer that was "only recently discovered." She was "surrounded by her closest family" when she died.

Alley is perhaps best remembered for originating the role of Lt. Saavik on Star Trek, as well as for her role as Rebecca Howe on six seasons of Cheers. Her film work included Drop Dead Gorgeous, It Takes Two and Toothless.

See more reactions and tributes, below.

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