Joe Wicks found out about his father's struggles with heroin addiction and explained that he had refused to suffer a similar fate.
The popular fitness coach said "Under The Skin" about Russell Brand's podcast, and he and older brother Nikki focused on exercise and sports instead.
"Because of my father's addiction and the damage I saw, I and Nikki stayed away from it," he said.
"We didn't smoke weed, we trained, trained and across the board I decided that this would not be my fate – that would not be my way."
Wicks said his father had been in and out of rehab throughout the fitness star's childhood.
However, the two now have a much better relationship.
"Now when my dad goes through a low phase, I text him and call him and ask how he's doing – I don't judge him addicted," said Wicks.
"He will always be addicted – he falls behind all the time."
Wicks, also known as The Body Coach, encouraged others to use exercise to keep your mind healthy.
He said, "Before you turn to binge eating, addiction, drugs, or antidepressants, try exercise.
" It's hard, my father says the last thing he wants to do when he goes through his lows are practice. But I say, "Daddy, you know how you feel about it – you always feel better."
Wicks is the father of daughter Indie, one, and son Marley, three months, with his glamorous model wife Rosie Jones.
The 33-year-old is currently holding 30-minute physical education classes on YouTube from his living room to encourage schoolchildren to remain active during the Coronavirus Pandemic .
He told Sky News: "It will really let off some steam – they feel a little positive and a little more optimistic and everyone should get involved.
" It's about getting energized, to feel motivated and positive, and we need that now more than ever. "