A former TV star battling dementia.

FOX's Jacquelyn Karl has more on the story:

Former "Partridge Family" star David Cassidy revealing he's dealing with dementia, but wants to stay focused and "enjoy life."

66-year-old Cassidy telling People Magazine there's a family history of the disease. His grandparents had it and he sensed "this was coming."

Cassidy's had his fair share of difficulties ranging from substance abuse to bankruptcy. The revelation coming as video footage surfaced of Cassidy's concert outside L.A. over the weekend when he slurred his words and fell off the stage.

Jacquelyn Karl, FOX News.

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