David Cassidy is suffering from memory loss due to dementia, he says, and will stop touring to focus on his personal life.
"I was in denial, but a part of me always knew this was coming," the 66-year-old entertainer told People in an interview published Monday.
The "Partridge Family" star struggled to remember familiar lyrics at a show in Agoura Hills over the weekend, the magazine said.
TMZ reported that Cassidy appeared to be drunk during the Saturday gig and posted video from the concert that showed him forgetting lyrics and even falling off the stage. However, sources told the website on Monday that the former teen idol, who has had substance-abuse problems in the past, was not drinking before the show.
Cassidy, whose hits included "I Think I Love You" with the Partridge Family, told People that his grandfather and mother struggled with dementia.
Cassidy has been talking about retiring from live performing for a while now. "I think now I am going to be semi-retired and retreat from live performing," he told the Decatur, Ill., Herald & Review in 2015, "except maybe for one or two gigs a year."
Now, he told People, "I want to focus on what I am, who I am and how I've been without any distractions."