Oliver and Kate Hudson rejected Kurt Russell's offer to adopt them.
The siblings' parents, Goldie Hawn and Bill Hudson, split in 1980, with the 'Death Becomes Her' actress going on to find love with the 'Silkwood' star in 1983.
And while Kurt, 73, has always had a great relationship with his partner's children, they turned down his proposal he legally make them his own children because they didn't feel the "need" for the paperwork, but also didn't fully understand what it meant.
Speaking on his 'Sibling Revelry' podcast, Oliver, 48, said: “I only say this because my dad — he was around for a little bit, then he bailed. We have a good relationship now, but it took a long, long, long, long time, but we’re there,.
“Kurt came into my life when I was six, five or six and essentially he raised me. I’m the man I am today because of him, right?
“There was a moment when he asked us, myself and Kate, if we wanted to be adopted, and we said no.
“Not that we were — you know, very aware of probably what it even f****** meant.
“We were six and 12 or however, I don’t remember the age, but we just said, ‘Well, we don’t need it. The love is right there.’”
And Oliver also reflected on how he and Kate, now 45, felt there was something lacking in their lives because of the absence of Bill.
He added: "At the same time, when you don't have your biological [parent] around, it's hard to replace that, no matter what.
"The love was there with Kurt, there's no doubt that he is my dad. I call him Pa. But there was always — not something missing, but there's that other side."
Kate previously praised Kurt for "stepping in" to be a "dependable father figure" for her and her brother when they were growing up.
Speaking on 'Today' in 2021, the 'Almost Famous' star said: "I think that estrangement is unfortunately quite common.
"I think it's important for people to talk about that. If they can't reconnect or if it's too challenging, that it's OK, right?...
"I have a great family. I have a beautiful mother. I have a stepfather who stepped in and played a huge, huge part in sharing what it is to have a dependable father figure in our life.
"But it doesn't take away from the fact that we didn't know our dad."
