John Ritter

Sitcom legend John Ritter who rose to fame on Three’s Company, died on set doing what he loved most. While working on 8 Simple Rules (he's pictured above with co-stars  Kaley Cuoco and Amy Davidson) Ritter complained of chest pains, collapsed, and began vomiting on September 11, 2003. Initially he was treated for a heart attack, but when he grew worse, he was diagnosed with an aortic dissection. Ritter died during surgery to repair the dissection that same evening.