The Grammy-winning guitar virtuoso, television host and Golden Globe-nominated actor, whose 50 years in the entertainment industry also include the Male Vocalist of the Year award from both the Academy of Country Music and the Country Music Association, has a resume of collaborations with artists such as Frank Sinatra, Phil Spector and the Beach Boys, with whom he toured in place of Brian Wilson in 1965.
Campbell, 75, was assisted in Tuesday night's interview on ABC by his wife, Kim Woolen.
"I'm going to be right in the middle of a sentence, man -- and it just goes ...," Campbell said.
Addressing his Alzheimer's Disease, Campbell appeared confused.
"I hadn't gotten it yet. In fact, I don't even know where it came from," the artist said.
"Yes, you've been diagnosed with Alzheimer's," interjected Woollen.
"What? I haven't felt it yet," Campbell chuckled. "I've always been forgetful anyway. I'm only what, 78?"
"Seventy-five," Woollen said.
The couple has been married for 30 years and Woolen's apparent devotion inspired Campbell to quote scripture.
"There's a verse in the Bible that says, 'If the man findeth a good wife, he's found a good thing,' and I found a good thing, or she found me," Campbell said.
Celebrity Breakups and divorces of 2014 [PHOTOS]