Shaun Cassidy and Adam Roarke in The Hardy Boys/Nancy Drew Mysteries (1977)

Shaun Cassidy and Ana Alicia in The Hardy Boys/Nancy Drew Mysteries (1977)

Shaun Cassidy in The Hardy Boys/Nancy Drew Mysteries (1977)

Shaun Cassidy, Edd Byrnes, Pamela Franklin, and Parker Stevenson in The Hardy Boys/Nancy Drew Mysteries (1977)

Shaun Cassidy and Nancy Morgan in The Hardy Boys/Nancy Drew Mysteries (1977)

Shaun Cassidy and Parker Stevenson in The Hardy Boys/Nancy Drew Mysteries (1977)

Shaun Cassidy, Edd Byrnes, and Parker Stevenson in The Hardy Boys/Nancy Drew Mysteries (1977)

Shirley Jones and son Shaun Cassidy at the "Scrooge" Premiere with Edward G. Robinson, c. 1970.

Shaun Cassidy, Angie Dickinson, Richard Widmark, and Willie Nelson in Once Upon a Texas Train (1988)

Shaun Cassidy and Willie Nelson in Once Upon a Texas Train (1988)

Shaun Cassidy, Pamela Sue Martin, and Parker Stevenson in The Hardy Boys/Nancy Drew Mysteries (1977)

Shaun Cassidy, Richard Widmark, Willie Nelson, and Dub Taylor in Once Upon a Texas Train (1988)