Former seventies teen idol David Cassidy found out he had slept with the same woman as his father just months before his dad's sudden death.

The Partridge Family star and his actor father Jack Cassidy spent time together on the latter's 1974 touring show, where David discovered Jack was cheating on his second wife Shirley Jones and drinking heavily.

In David's autobiography Could It Be Forever?, he recalls, "What I remember most about that weekend was spending the night with one of the girls from the show, only to find out she had already been sleeping with my dad. When she told him she'd had sex with me, I think this probably sent him over the edge.

"He appeared to suffer a complete breakdown and was committed to a mental hospital for 48 hours."

A week later, Jack recovered and met up with David to ask him for $10,000, which the teen star refused to hand over. It turned out to be the last time they saw each other. On December 12, 1976, Jack died in an apartment fire in West Hollywood.

(This news article provided by World Entertainment News Network)