Glen Campbell. (Dan Steinberg/ASSOCIATED PRESS)

Campbell’s wife Kim said they have gone public with the diagnosis ahead of the country legend’s farewell tour set for this fall. “Glen is still an awesome guitar player and singer,” she told the magazine. “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?’ ”

That could be a real concern for the country legend, who was sentenced to 10 days in jail for extreme drunk driving and leaving the scene of an accident in 2004.

“I still love making music,” the “Rhinestone Cowboy” singer said. “And I still love performing for my fans. I’d like to thank them for sticking with me through thick and thin.”