Greg James has revealed that his job has made him less self-conscious.
Having bared all in a YouTube parody of Miley Cyrus's Wrecking Ball video, the Radio 1 DJ admitted he is no longer shy.
"I don't have any shame any more," he said. "Since working at Radio 1, I think you don't take anything too seriously."
The 28-year-old DJ and TV presenter, who rowed down Africa's treacherous Zambezi River for Comic Relief in 2013, has been training for the Great North Run in September, where he is now aiming for his personal best.
"They're things I never thought I'd ever do, like running marathons, going down the Zambezi and stuff," he said. "If I talked to my 13-year-old self now, and said, 'This is what you're doing', he'd never believe me. He'd be too shy and unconfident and worried about everything.
"Now I feel like my job has given me a lot of confidence, so doing things like the Zambezi has been mental. It was really scary. Canoeing past hippos, which are about three metres away, is insane. They are not like [the game] Hungry Hippos, let me tell you!"
Greg, who is also backing a campaign to get more people active, admitted there must be a lot of pressure for teenagers today.
"It must be a nightmare to be a teenager in 2014. I'd hate it," he said. "There is just so much pressure. I can't imagine there being social networks at school. You must get upset and distracted by the wrong things."
:: Greg James is participating in the Bupa Great North Run on September 7, and supporting Bupa's Your First Step Campaign. For more information visit www.bupa.co.uk/running.