Bear Grylls has a clause in his contract for his current show stating he won't strip on camera.
The 43-year-old adventurer never used to have any issues stripping off on screen to have a wash out in the open, but has come to a "no nudity" agreement with bosses of his new programme 'Running Wild', in which celebrity guests Kate Hudson, Julia Roberts, Mel B, Julianne Hough and Lindsay Vonn have taken part, because he wants to come across as more "modest".
A source told The Sun newspaper: "A decision was made by Bear not to take his clothes off when he on the celebrity shows. While in the past he has been totally relaxed about getting naked, with stars he is being much more modest. There is a two fold thought process -- first he doesn't want to embarrass any of his fellow adventurers, and secondly his concern is that they might strip off too. That sounds fun, but being a married father of three kids that may not send out the right message.
"Now the furthest he goes is keeping his under garments on. And he tells the stars before they join him, that for two days they will not wash their bodies. That way he stays out of trouble."
And Bear's wife Shara, with whom she has three sons, thinks it's "hilarious" that he's decided to ban nudity on his shows as she knows that no celebrities will be "interested" in his bare bottom.
The insider explained to the publication: "When he is with the female stars he is more nervous than they are about showing skin or being too vulnerable. Shara knows that her husband is a devoted family man. She jokes that none of the celebrities would be interested in him anyway."