Almost seven months after David Cassidy died of organ failure on Nov. 21, a new A&E documentary titled "David Cassidy: The Last Session," filmed just before his death, exposes shocking revelations about the "Partridge Family" star's health.In a teaser clip for the special, Cassidy calls an A&E producer named Saralena to discuss a diagnosis. "I just met with the doctor, and my liver ... I have a liver disease," he tells her. "My life has changed dramatically. The first few days I was unconscious and near death. The last week or so my memory has come back."Prior to his death, Cassidy revealed to the public that he had dementia, which causes long-term and often gradual memory loss. The singer even appeared on Dr. Phil's show in March 2017 to talk about his experience with the disease."I wanted to come and talk to you because I know how broad your influence and your audience is ... to let them know I'm really OK," he told Dr. Phil, adding that he was diagnosed two years before.However, in the upcoming A&E documentary, Cassidy confessed, "There is no sign of me having dementia at this stage of my life. It was complete alcohol poisoning. And the fact is, I lied about my drinking."In 2014, Cassidy's struggles with substance abuse hit rock bottom when he was arrested for three DUIs in three years, and a judge ordered him to spend 90 days in alcohol rehab. According to People, he told family and friends soon after that he had stopped drinking altogether.However, the A&E documentary tells a different story. "I did it to myself," he said in the special. "I did it to myself to cover up the sadness. And the emptiness.""David Cassidy: The Last Session" premieres Monday, June 11, on A&E.