Country music icon GLEN CAMPBELL has been diagnosed with Alzheimer's disease. He's been suffering from short-term memory loss for years, but wasn't diagnosed until six months ago. He's 75 years old. Glen and his wife Kim decided to talk about it NOW because he's doing a farewell tour in the fall.(--No word yet on those dates.) Kim told "People", quote, "Glen is still an awesome guitar player and singer. But if he flubs a lyric or gets confused on stage, I wouldn't want people to think, 'What's the matter with him? Is he drunk?'" Glen adds, quote, "I still love making music. And I still love performing for my fans. I'd like to thank them for sticking with me through thick and thin." He's also releasing a new album on August 30th. It's called "Ghost on the Canvas". You may remember a few months ago when we talked about the all-star guest cast Glen assembled for the album.