NYP2003091201 - NEW YORK, SEPT. 12 (UPI) - Actor John Ritter, star of his current TV series "8 Simple Rules For Dating My Teenage Daughter," collapsed and died while on the set at the age of 54 from a heart attack. Ritter was best known for his work in the TV series "Three's Company." rlw/ep/Laura Cavanaugh/FILE UPI