Leo, the Maine Coon crossbreed cat who played Church in the 2019 remake of Pet Sematary, has died just a month after the film's release.

While four different cats played the iconic Church, it was the shelter cat Leo who was featured prominently for his portrayal of the undead animal character. Unfortunately, it will be his last role, as his trainer has announced his passing on social media.

According to owner and animal trainer Kirk Jarrett, Leo died of feline arterial thromboembolism, which is also known as saddle thrombus and common among Maine Coon cats.

Cat Actor Dies After 'Pet Sematary'

Jarrett adopted Leo after the pair filmed the second big screen adaptation of Stephen King's horror novel, setting him up with an Instagram account that now has nearly 20,000 followers.

It is on this social media platform that Jarrett announced the death of the cat, posting a touching tribute on Thursday, May 30.

"It is with deep sadness that we tell you that Leo has passed away," Jarrett wrote on Leo's Instagram page. "He will be forever missed by his human and fur family. May his star always shine bright!"

Leo, Other Cats As Stars Of 'Pet Sematary'

In the 2019 remake of the classic novel, Church comes back from the dead as an ominous version of a beloved family pet who gets run over on the highway.

According to Jarrett and fellow Pet Sematary animal trainer Melissa Millett, Leo ended up being used for most of the undead scenes due to his distinct stare and expressive face.

"Leo is a confident sit-stay cat," Jarrett described to AV Club in an interview on April 2019. "His role is as the undead Church; that was his whole purpose, to be the poster child. The cat you see all across the different platforms, and in the trailer, almost any time he's in in the undead makeup — that was Leo."

"Part of it was that he's just got such a cool look, different from any other cat I've seen. He's got this beautiful face, and these eyes that are so expressive," Millett added, saying that Leo particularly excels at quiet staring.

Feline Aortic Thromboembolism

This condition, which is often called FATE or saddle thrombus, is a sudden condition that paralyzes a cat and puts it in extreme pain, according to Veterinary Partner.

A saddle thrombus is actually a blood clot that broke off from a larger clot in the heart, traveled down the aorta, and attached at the saddle. This blocks off the blood supply to the rear limbs as well as sets off metabolic reactions that could result in circulatory shock.

About 89 percent of cats with saddle thrombus have an underlying heart disease that makes them prone to blood clots. However, it's difficult to detect. In 76 percent of cats found with a saddle thrombus, a FATE episode was the first symptom of a heart disease.