According to multiple reports, the actor, who played Martin Crane for 11 seasons on the beloved show, died in Chicago while in hospice care on Sunday.
John Mahoney has died, his rep confirms to ET. He was 77.
The rep reveals that the actor, who most notably starred for 11 seasons as Martin Crane -- father to Kelsey Grammer and David Hyde Pierce's characters -- on the beloved NBC sitcom Frasier died in Chicago on Sunday "after a short illness." According to multiple reports, he was in hospice care when he died.
Mahoney, who earned two Emmy nominations for his role on the long-running series, also starred in such films as Say Anything and Barton Fink. Recently, he also had a recurring role on Hot in Cleveland, where he played a love interest of Betty White.
Mahoney was born in Lancashire, England, becoming a U.S. citizen in 1959. Before taking up theater and acting in 1977, he served in the U.S. military and worked as an English teacher at Western Illinois University. Mahoney was unmarried and never had children.
After he died, many fans took to social media to mourn, including Ken Jeong, who tweeted, "Rest In Peace, John Mahoney. Say Anything is one of my favorite films of all time."
Rest in peace, John.