Joe Wicks has admitted that his life was changed by his father's heroin addiction.
The Body Coach - who shot to fame during the lockdown thanks to his online PE lessons - discussed the problems he faced in childhood while on BBC Radio 4's Desert Island Discs.
He said that seeing the impact that drugs had on his father while he was growing up meant that he has never been tempted to try them himself.
"Because of my dad's life, I didn't go near it," he told the programme.
"I was scared of it and I got into exercise and fitness and so his mistake changed my life."
His father's addiction was caused by "childhood trauma", he added.
"I just don't regret anything I've gone through or anything I have been through with my mum and dad, I'm just proud of who I am," he said.
Wicks also got emotional while recalling a time he told someone at school that he hated his dad.
"I only ever said that once, I have never really admitted that to my dad, but it was just a reaction and I felt so bad because I didn't hate my dad, I hated what drugs were doing to him and doing to my family," he said.
"It was an angry thought and I suppose I let it out and I felt instantly bad and I remember just thinking, 'What a horrible thing to say about your dad'."
He said that he was not an unhappy as a child and just "cracked on" with things, adding: "It was all I knew."
"He's had times when he's relapsed but today he is clean and that's the most important thing, but when I was a teenager I found it difficult.
"I didn't understand, I was angry but now as an adult I understand. I have got more empathy."