Brian Cox learned "how to survive" after the passing of his father.
The 'Succession' star says he was left with "nobody" after he lost his dad when he was just eight years old, because his mother "couldn't cope with any of it", and his older siblings already had families of their own.
And Brian believes the experience forced him to build his own "survival mechanism" to keep himself going.
Speaking to David Tennant on his 'David Tennant Does A Podcast with...' series, he said: "It was a very odd time. My mother had clearly, she actually ran away from home at one point. My dad was a wee businessman, he was a wee shopkeeper, but very, very loved. Very respected.
"Unfortunately, he ended up in a very, very bad physical situation. Then he developed, very quickly, pancreatic cancer, and by the age of 51 he was gone. My mum couldn't cope with any of it, because the businesses and all that, which finally collapsed, and she had a series of nervous breakdowns.
"You actually learn to either sink or swim in that situation. There's nobody. My sister's were there, but they were married. They had kids ... I was between various pillars and various posts. I just learned this survival mechanism, really. How to survive ... It's marked me a little bit."
The 74-year-old actor was also pushed to stifle his emotions at the time, because his family "never talked about anything".
He added: "My family was Catholic. There was this sense of, you never talked about anything. My mother's greatest praise if I did something, she'd say, 'Oh that's quite nice.' And I'd go, 'Is that it?' Well, that's it. Because they didn't know.
"I describe it as conditioned ignorance, which is ignorance where people are really kept in the conditions of ignorance. The Catholic Church certainly doesn't help. Therefore, people lived in this way where they didn't express themselves."
And although Brian did "cry a bit" at his dad's funeral, it wasn't until he became a student at LAMDA (the London Academy of Music and Dramatic Art) when he was 17 that he started to open up.
He explained: "I cried a bit. My dad's funeral, in retrospect, and it sort of had a profound effect on me. The 60s were such an amazing time of being welcomed. That was the great thing about when I was a student; I was welcome. The country took care of me. I was given a very good grant with a very good living allowance."
'David Tennant Does A Podcast With...' is available on Apple, Spotify and all podcast providers.