He was one of the most familiar faces on TV for years.
Actor John Ritter died from a heart problem at a hospital in the Los Angeles area late Thursday night. He was 54, and was just days short of his birthday.
His publicist says Ritter died from a flaw in his heart that apparently had gone unrecognized.
Ritter's portrayal of the bumbling but lovable Jack Tripper helped make the comedy series "Three's Company" a smash hit in the 1970s. Ritter revived his TV career recently with an ABC sitcom called "Eight Simple Rules ... For Dating My Teenage Daughter." The show was scheduled to begin a second season.
He also appeared in more than 25 television movies and a number of films.
Ritter's longtime assistant says he fell ill on the set of his new show Thursday.