In 2009, PEOPLE caught up with the Partridge Family star and the former Melrose Place actress to discuss their unique father-daughter relationship.
Though Katie was raised by her mother — former model Sherry Williams — and her stepfather, Richard Benedon, Cassidy still played an important role in her life.
“Because I didn’t raise her, I didn’t have to parent her,” he said. “I’m always here and totally nonjudgmental.”
“To be able to go to someone I’m genetically linked to, tell them anything and know that they’re not going to judge me — it’s unbelievable,” Katie added. “It’s nice when your dad can be your friend.”
But Cassidy wasn’t just a friend — he was also a strong mentor with great advice.
“Do not work for money,” he told his daughter. “Do not work for fame. Work for the work. And if you get a great role and they offer you nothing, take it.”
And Katie took that advice. “That’s all he’s said, and I’ve taken the advice,” she told PEOPLE.
Despite their close relationship seven years years ago, Cassidy — who recently revealed that he has been diagnosed with dementia — confessed earlier this year that he was no longer in contact with his eldest child.
Although the father-daughter duo had a falling out, he was still impressed with the woman she has become.
“I’m proud of her,” added Cassidy. “She’s very talented. It’s hard for me to even accept how old she is now, like 30.”
Cassidy also had a son, Beau, whom he was close to. “He’s just one of the best people you’ll ever meet in your life and it’s that that I’m proud of,” Cassidy said.