Ritter had been rushed to hospital after suffering from an 'undetectable flaw in his aorta'.
Ritter, who would have been 55 next week, starred in the hit television series 8 Simple Rules For Dating My Teenage Daughter and Three's Company.
The Emmy Award winner was born on September 17, 1948. He is survived by wife Amy Yasbeck, their daughter Stella and three children, Carly, Tyler and Jason, from his previous marriage to Nancy Morgan.
Photograph: Getty Images