"I always believed grief for a public figure is a private matter," he said in a statement provided to EW, "but I will say I loved her."
NBCU Photo Bank/NBCUniversal via Getty Images Kelsey Grammer and Kirstie Alley on 'Cheers'
Ted Danson, one of the original main cast members of the show, also remembered Alley as "truly brilliant" for her performance on the series.
"I was on a plane today and did something I rarely do. I watched an old episode of Cheers. It was the episode where Tom Berenger proposes to Kirstie, who keeps saying no, even though she desperately wants to say yes," Danson said in a statement to EW. "Her ability to play a woman on the verge of a nervous breakdown was both moving and hysterically funny. She made me laugh 30 years ago when she shot that scene, and she made me laugh today just as hard. As I got off the plane, I heard that Kirstie had died. I am so sad and so grateful for all the times she made me laugh. I send my love to her children. As they well know, their mother had a heart of gold. I will miss her."
Through a representative, Rhea Perlman, who won four Emmys for her role on Cheers, also expressed remorse over Alley's death in a statement to EW.
"Kirstie was a unique and wonderful person and friend. Her joy of being was boundless," she 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. She had massive Halloween and Easter parties, and invited the entire crew of the show, and their families. She wanted everyone to feel included. 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."
On Twitter, John Ratzenberger said it was "so sad" to learn of Alley's death, which occurred after the star's brief battle with cancer, according to an Instagram post from her children.
"So very sad," Ratzenberger repeated. "God Bless you and keep you Kirstie Alley."
Before she starred in beloved films like Look Who's Talking and Drop Dead Gorgeous, Alley joined Cheers in its sixth season as Rebecca Howe, who eventually took over as manager of the titular bar.
For her performance on the show, Alley won an Emmy for Outstanding Lead Actress in a Comedy at the 1991 ceremony, atop winning a Golden Globe for the role as well.