Retired Tonight Show legend Johnny Carson has been diagnosed with emphysema. However, a rep for the 76-year-old entertainer insists he is otherwise in good health. Carson was prompted to speak out about his condition after tabloid reports said he was seriously ill with the respiratory disease. "He does have emphysema, but he's dealing with it the best he can and it's not causing him any major problems," spokesman Jeff Sotzing tells The Associated Press. "He's in great shape." Carson — who underwent quadruple bypass heart surgery three years ago — was known to smoke on the air during his 30-year Tonight Show reign.