Kaley Cuoco felt like she'd 'lost her dad' when John Ritter died

Kaley Cuoco felt like she'd lost her own father when John Ritter died.

The Big Bang Theory star worked with Ritter on family sitcom 8 Simple Rules playing his onscreen daughter and she was left devastated when the actor passed away on September 11, 2003 after suffering an aortic dissection on the set of the show.

Kaley attended the John Ritter Foundation for Aortic Health's annual Evening From the Heart Gala in Los Angeles on Saturday night (12.09.26) and she fought back tears as she spoke about her affection for the late actor. She told the audience: "I always cry when I talk about him ...

"When he passed away, I don’t want to get dramatic, but I can truly say that was one of the worst days of my life.

'I remember having to remind myself that I wasn’t his kid. I remember for weeks after, I was like: 'Gosh, I feel like I lost my dad'."

During her speech, Kaley also opened up about meeting John for the first time at a table read for the show and revealed he was already showing his paternal side.

Kaley - who is pregnant with her second child - said: "[I was playing the] hot girl before I was knocked up ... Young and cool and hot, so I wore like the hottest outfit I could ever find for this table read, like nothing. It had these little spaghetti straps, just ridiculous ...

"He gives me a big hug, and he looks at me, and he takes off his jacket, and he puts it on me and says: 'Don’t ever wear that again'. It was the best."

Kaley also insisted she still sees John as a guide as she navigates her Hollywood career without him, saying: "He was so funny.

"I took all that with me in life and the jobs I had after. He always has been the north star in my career and somebody who I adore."

The gala raised funds for research and to support families who have lost loves ones to aortic dissection. It was hosted by John's widow, Amy Yasbeck, and his son, Tyler Ritter, and featured a special reunion by the cast of TV show Wings.