Reality TV Star Bear Grylls Tries Khakis On for Size Discovery Channel Joe Resto, left, Bear Grylls and Sean Lacoste work on a shelter on the reality TV show "Man vs. Wild." ON a recent morning, Bear Grylls, the star of the Discovery Channel survivor show "Man vs. Wild," was dressed in a rugged ensemble of army-green work shirt and cargo pants, a no-nonsense knife strapped to one leg. Standing in the middle of a pine forest with his jaw purposefully clenched, he looked ready for battle. Alas, there were no snakes or grizzly bears to wrangle into submission. Mr. Grylls, 37, was not in the Rockies fending for his life, but less than an hour from Los Angeles, filming a commercial for Degree deodorant. Not that it was any easier than filming his TV show, which drops Mr. Grylls in the most God-forsaken pockets of the planet and watches him face off against blinding ice storms and insect-drenched jungles. "It's quite difficult," he said, walking away from the cameras after what felt like the 80th take, a pair of young makeup artists in skinny jeans trailing behind him. Lately, this kind of "labor" has been taking up more of Mr. Grylls's time, as he finds himself transitioning from a wacky British television character known for drinking his own urine and sleeping inside a dead camel (for hydration and warmth, respectively), into a more mainstream celebrity. Dockers recently selected Mr. Grylls as the face of its campaign, which features the boyishly handsome adventure fanatic tramping through Central Park in slimly tailored khakis and a narrow tie, looking more like a young Gregory Peck than Crocodile Dundee. The images have already caused a stir: Out magazine's Web site published a Bear Grylls "Swoon Alert" wondering why Dockers was forcing the "dreamy nature explorer" to wear shirts in the photos. In May, Mr. Grylls's memoir, "Mud, Sweat and Tears," and live show will arrive in the United States. The book, his 11th - he's also written on survival techniques and for children - is already a best seller in Britain and Australia. His growing empire also includes a "Man vs. Wild" video game, an outdoor clothing line sold at REI and Walmart, and an iPhone app. But if Mr. Grylls is going corporate and high tech, it is with some reluctance. Though "Man vs. Wild" has been on the air since 2006, he insists he hired a publicist last year "so I don't have to do P.R.," and that he's "still always the scruffiest person at any meeting." Sitting in an office building in Santa Monica, Calif., one rainy afternoon, having just stepped out of a conference with members of his Bear Grylls Ventures team, he was still dressed in his running clothes from earlier in the day. Mr. Grylls was perched on a leather chair, his bright-blue Vivobarefoot sneakers propped up on a table, as he took swigs from a Diet Coke. He was much more keen to discuss recent adventures than anything having to do with his brand. For instance: the 5,000-mile trip he took with friends last summer on an inflatable boat through the Arctic Ocean's Northwest Passage, a treacherous journey. "We had a huge adventure, we had monster storms," he said, his baby-blue eyes growing wide. We needed bear spray to keep the bears away, because there were lots of bears up there when you're camping at night. Then there was the time he and Jake Gyllenhaal, a friend since the actor appeared on "Man vs. Wild" last season, decided to go for a leisurely boat ride in the Santa Monica Bay. We pull out of Marina del Rey and, I'm not joking, it's like standing waves, 30 feet high. Absolute monsters," Mr. Grylls said. We just got smashed to bits. "Hanging with Bear is not for the faint of heart," Mr. Gyllenhaal wrote in an e-mail. He is always pushing the limit, and it is infectious to be around. Or to hear about: It is Mr. Grylls's knack for exuberant, slightly over-the-top storytelling, enhanced by a buttery accent, that might resonate with the 1.1 million viewers who tune into "Man vs. Wild" each week. The show is particularly popular with men in their mid-30s. Unlike more conventional Robinson Crusoe types, like Les Stroud, the star of "Survivorman," also on the Discovery Channel, Mr. Grylls performs before the camera, joking, charming and narrating his exploits with a melodramatic goofiness. Biting into an enormous maggot (a protein-rich survival food, evidently), he dangles the writhing specimen in front of his mouth and grimaces in horror before slowly crunching down. After the insect explodes in his mouth, he makes a stomach-turning and somewhat outrageous joke about how it tasted.