Saying that he's been diagnosed with the same condition that struck his mother and grandfather, singer David Cassidy has revealed that he is fighting dementia. The star whose career was launched by 1970s TV show The Partridge Family had recently told fans that he was on a farewell tour."I was in denial, but a part of me always knew this was coming," Cassidy, 66, tells People magazine, in an interview about his condition.The revelation comes after two recent developments: Earlier this month, Cassidy stated that he would no longer tour after 2017; and over the weekend, the website TMZ posted a video from his Saturday night show, in which the star seems to struggle to recall lyrics and maintain his balance.Last week, as Cassidy discussed the last shows he had planned to play in California, he said: "I just can't tour anymore. I know it's time."On his Facebook page, Cassidy had recently said he wanted to perform until the end of the year, urging fans to come see the final concerts in what he said were 49 years of touring."I'm not going to vanish or disappear forever," Cassidy wrote.But it now seems that his health concerns have forced Cassidy to hasten his retirement date. His mother, Evelyn Ward, died at age 89 after struggling with dementia for years, Cassidy has said.The former teen idol has been an active supporter of the Alzheimer's Association, auctioning off some of his old costumes to benefit the group after his mother's death late in 2012. In recent years, Cassidy has also been forced to auction a house and other items as part of bankruptcy and divorce proceedings.The performer's official page also recently highlighted a 1972 interview he did with the BBC, in which Cassidy talked about his life as Keith Partridge — and how he tried, without success, to elude masses of fans. At the end of that chat, he was asked if he worried about how ephemeral his fame and success might be."I don't worry about it at all," Cassidy said. "I think by the time that it does kind of die out, I'll be wanting it to." Copyright 2017 NPR. To see more, visit http://www.npr.org/.