The unexpected death of actor [John Ritter], who rose to fame in the 1970s as a wacky bachelor in the hit ABC series "Three's Company," not only shocked fans and colleagues but delivered a powerful blow to the ailing network's hopes of reviving its fortunes through the comedian's latest sitcom.

"John was the reason for the show," said producer Ted Harbert, a former network TV executive and a longtime friend of Ritter's. "He's irreplaceable."

ABC decided to premiere "8 Simple Rules" along with other fall hopefuls on a single Tuesday night. To help sell the show, ABC used Ritter's return to TV comedy as a publicity hook and promoted the program relentlessly, including in McDonald's restaurants.