Lance Armstrong has revealed one of the reasons that made him finally confess to doping during his cycling career and his seven Tour de France victories.
Speaking in the second part of his interview with Oprah Winfrey, Armstrong said that when he found out his 13-year-old son Luke was defending him on social media, he had to tell him the truth.
Armstrong began to tear up when telling the story of how he confessed to Luke.
"I saw my son defending me saying, 'That's not true, what you're saying about my dad is not true'," Armstrong told Winfrey.
"He never asked me. He never asked 'Dad, is this true?'
"He just trusted me. At that point I decided I had to say something. It was out of control."
Armstrong said he revealed the truth to his son and twin daughters Isabelle and Grace over the Christmas holidays.
"I said, 'There's been a lot of questions about your dad. I want you to know that it's true.'
"The girls and Luke, they didn't say much. They just accepted it.
"I told Luke 'Don't defend me anymore.'"
Armstrong added, "Thank god he's more like Kristin [Armstrong's former wife] than he is like me."
Earlier in the interview, Armstrong described his lifetime ban from all sport as being “like a death penalty”.
Armstrong said he wished he could have gone back to the first USADA investigation and made a confession in order to receive a lesser punishment, but now has to suffer through a lifetime ban from all sanctioned sport.
Armstrong cited the fact that other cyclists who had confessed to doping received bans of as short as six months.
"I deserve to be punished," Armstrong said.
"I'm not sure I deserved a death penalty."
While Armstrong said he did not want to compete in another Tour de France, he expressed frustration at not being allowed to run in events such as the Chicago Marathon or the Austin 10k.
"I'm a competitor. It's what I've done my whole life. I love to train. I love to race," Armstrong said.
Armstrong was asked if he hoped USADA would overturn his lifetime ban from sport as a result of his confessions to doping.
"Selfishly, yes," he answered.
"But realistically, I don't think that's going to happen."
Armstrong also told of his 'lowest moment' since the stripping of his seven Tour de France titles.
Armstrong said he began feeling "humbled and shamed" when his sponsors, including Nike, Oakley and Trek, dumped him but that stepping away from his cancer foundation Live Strong was the most difficult thing to do.
"The one thing that I didn't think would leave was the foundation," Armstrong said.
"And that was the most humbling moment.
"To step down as chairman and stay on the board, that wasn't enough for the people, for our supporters.
"A couple of weeks later another call came saying we need you to consider stepping down."
When he was 25 years old Armstrong was diagnosed with stage three testicular cancer. Doctors gave him less than a 50 percent chance of surviving.
After beating cancer, Armstrong started up the Livestrong foundation to raise cancer awareness and to give inspiration to cancer sufferers.
Armstrong severed all ties to Livestrong last November.
"The foundation is like my sixth child," he said.
"To make that decision, to step aside, that was big. I wouldn't say I was forced out, but I was aware of the pressure.
"It hurt like hell. That was the lowest. The lowest."
Armstrong was then asked what he would say to the millions of fans who supported him and the millions of people who wore the iconic yellow 'Livestrong' wristband.
"I understand your anger, your sense of betrayal," Armstrong said.
"You supported me forever, you believed in me and I lied to you. And I'm sorry.
"I will spend, and I am committed to spending, as long as I have to in order to make amends."
"Do I have remorse? Absolutely.
"For me this is just the first step. These are my actions, I'm paying the price and I deserve it."