Leo played the undead cat named Church in this year's remake of the horror classic.
His death comes just weeks after the film's release.
Leo is featured in the official trailer for "Pet Sematary," which is based on Stephen King's terrifying novel.
Animal trainer Kirk Jarrett announced the sad news on an Instagram account dedicated to Leo.
It shows a picture of Leo sitting in front of a fireplace, along with a message.
"It is with great sadness that we tell you that Leo has passed away. He will forever be missed by his human and fur family. May his star always shine bright," Jarrett wrote.
Jarrett did not release Leo's cause of death.
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