They are the finest athlete of our time. NFL stars to olympians. And they're taking it all off. Why? Here's ABC's linsey Davis. Reporter: It is, after all what we come into the world wearing. Our... See More
They are the finest athlete of our time. NFL stars to olympians. And they're taking it all off. Why? Here's ABC's linsey Davis. Reporter: It is, after all what we come into the world wearing. Our birthday suit. But when you put it on the cover of a magazine, it has the cover to shock, anger, intrigue, and sometimes inspire. We're not going out there just trying to be titillating, we're trying to prove a point about the athletic form. Reporter: ESPN the magazine's sixth annual "Body" issue, showcasing the world's most elite athletes, all posing tastefully nude. It didn't easy getting star athletes to take their clothes off. They're human beings. As proud as they are of their bodies they're still anxious about the idea of getting naked in front of people for a photo shoot. Reporter: Five-time wimbledon champion Venus Williams recalls feeling a little shy. I was joking that I wish I would have like really just done 1,000 abs a day to compete with athletes that are just ripped. But I'm probably never going to be ripped. I'm powerful on the court, that's all that matters. Reporter: But soon they forget the cameras are even there. In the first two or three frames, the athletes forget they're naked, they don't care that they're walking around naked on set, it gets very comfortable very quickly. Reporter: 18-time olympic gold medalist Michael Phelps and "Dancing with the stars" favorite Amy Purdy just some of the 22 athletes baring it all. 23-year-old hawaiian surfer beauty coco ho ditches the wet suit and surfs naked. Sometimes it's the thrill of the wave you get, the adrenaline of a really good barrel. Reporter: Not all the bodies are young athletes. 78-year-old hall of fame golfer Gary player was in last year's issue. And this year, 49-year-old light heavyweight world champion Bernard Hopkins, the oldest title winner. Some of the photos have caused controversy. Last year tennis star radovanska was dropped from a catholic youth group in Poland for her immoral behavior. Something we feel is severely offensive, we have a conversation about it, then we're glad it's generating that conversation. For her she was proud of her pictures. Reporter: Most of the athletes are fearless on set. The standout star from this year's shoot? Certain yeserga Baka was upset there weren't more parts of his body to work out. Reporter: Whether on the field or on the set they come with their top game, ready to show the world what we're really made of. For "Nightline" I'm linsey Davis in New York.
This transcript has been automatically generated and may not be 100% accurate.