Jimmy Coco is the first to admit that he has the best job in the world. When he shows up for work, he says, “Somebody’s getting naked, and it’s not going to be me.”

Coco is a professional spray tanner based in Los Angeles, and by his account the first mobile operation in the spray tanning business. For a cost of between $250 and $350, he’ll visit clients at their homes and give them a full-body tan in the privacy of their shower or his tanning tent. Coco has a long list of devoted celebrity clients — he’s created faux tans for Heidi Klum, Megan Fox, Victoria Beckham, and Katy Perry, among others — and he believes that part of his success is due to his ability to put the awkwardly nude at ease. “I‘m able to connect with somebody who’s about to take off their clothes,” he says.

It’s a weirdly specialized skill, and one that only could exist in 2011, the dawn of a new golden age for tanning. If you’ve turned on a TV recently, you’ve probably noticed a startling rise in the number of bronzed faces. There was a time when you could count the number of tanned celebrities on one hand. There was George Hamilton and… well, George Hamilton. People have always loved to tan, but it was a guilty pleasure and a bad habit, akin to smoking (and just as likely to cause cancer.) But today, tanning is not just fashionable again, but socially acceptable. Everyone from politicians like John Boehner to reality stars like Nicole “Snooki” Polizzi to British royalty like Kate Middleton are sporting tanned faces. The difference is, they’re not getting their tans from the sun, which has long been known to cause melanoma and skin cancer, or even UV tanning beds, which were categorized as “carcinogenic to humans” by the World Health Organization in 2009. Today’s tan comes in aerosol form, and it’s never been more popular. According to market research group Mintel International Group, the sun protection and sunless tanning market “has increased by nearly 50% since 2005,” with an estimated worth of $701 million in 2010.

It’s a remarkable transformation for an industry that was once widely considered a joke. Mystic Tan, the first mainstream spray tan introduced in 1998, often resulted in an unconvincing orange glow, making a person’s skin look like it’d been dipped in Cheetos. But thanks to recent advances in spray tan technology, the “artists with a spray gun,” as Coco describes himself and his peers, have gone from maligned outsiders to the most sought-after specialists in the beauty and vanity trade. “Last year, my phone didn’t ring at all,” Coco recalls. “I had to call myself to make sure my phone was still working. But this year, I’m getting more requests from new clients than I can handle.” Rick Norvell, the president of Norvell Skin Solutions, a salon and sunless tanning product manufacturer based in Alexandria, Tennessee, has experienced a similar spike in business. “My (spray tanning) sales have grown by 50% this year,” he says. “I make about six thousand gallons of spray tan solutions every week.”

The biggest boon for spray tanning isn’t just its relative safety when compared to direct sunlight tanning. Spray tanning has become an accepted and even trendy beauty practice almost solely because of the growing number of public personalities who aren’t afraid to flaunt their spray tanning addictions. Stars like Eva Longoria Parker, Olivia Wilde, Miley Cyrus and Real Housewife Kelly Killoren Bensimon make no secret that their golden complexions are store-bought. And some of them even shill for spray tanning products. Kelly Osborne, the “self-esteem ambassador” for self-tanning line St. Tropez, has called spray tans a “confidence booster” and helped her “look and feel beautiful from the outside in.” The increased visibility has spawned a wave of new customers. When Kate and Pippa Middleton caused a media stir with their fake tans at the British Royal Wedding in April, sales for sunless tanning products to spike by 219 percent at the popular U.K. department store Debenhams.

“Spray tanning is celebrity driven and everybody knows it,” says Lorit Simon, the president at Tanning Vegas, an airbrush tanning company in Las Vegas. She giddily recounts how her new product, a self-tanning spray called Sevin Nyne — which purportedly contains ingredients like goji berry and chardonnay — was featured on the MTV reality series The Real World. “It was sitting right there on the counter,” she says proudly. But not all celebrity endorsements are as uncomplicated. Simon created Sevin Nyne in 2009 with the help of Lindsay Lohan — one of her regular tanning customers — and their relationship has since soured. There have been numerous lawsuits filed between the former business partners, most recently from Simon, who filed a claim in February that Lohan has failed to pay an outstanding bill for $41,031.60 for spray-tanning services between 2007 and 2009. (Simon is unable to comment on the case, which is ongoing.)

While her legal battles with Lohan may be unpleasant, the publicity has definitely helped business. Not long ago, Simon says, spray tans were being purchased mostly by “old people, like in their 30s.” But now, she says, thanks to the very public spray tanning enthusiasm of celebrities like Lohan, Paris Hilton and the Jersey Shore tanning contingent, her customers are skewing young, from teenagers to pre-teens. “We’ve tanned as young as five to seven years old but that is very very rare,” says Simon. And the elder customers have just gotten older. Her oldest client was an 87-year-old women who was preparing for a cruise and wanted to “rock her tan in a bathing suit.”

Anna Stankiewicz, the “Master Airbrush Tanning Guru” at Suvara, a sunless tanning salon in New York, says her clientele have become increasingly older and more professional. “I tan a lot of very powerful older businessmen,” she says, none of which she’ll name. Confidentiality agreements, whether for A-list celebrities or high-profile CEOs, have become a standard practice in spray tanning. As have steep price tags. Stankiewicz charges $100 for a spray tan, which she initially worried was too high until reconsidering the buying habits of Suvara’s clientele. “These are women who regularly spend $300 to get their makeup done for an event,” she says. “And they just wash it off the next day. With a spray tan, it lasts five to ten days. You get a lot more for your money.”

Customers aren’t just paying for the tanning solution, of course. They’re also paying for the artistry. Rick Norvell, a pioneer in sunless tanning — he’s been in the industry since 1983 — says that a spray tan specialist, unlike the Mystic Tan spray booths or home self-tanning applications, can get to those hard-to-reach spots where the sun don’t shine. “You can spray armpits, you can spray between the thighs, you can have them lift their boobs and spray under their boobs,” he says. “You can even spray under their buttcheeks, where everybody gets a little smiley grin because of the butt overlap.”

Michelle Sturiale, the resident airbrush artiste at Manhattan’s the Rita Hazan Salon — who has sprayed everyone from the Olsen Twins to Monica Lewinsky — knows tricks of the trade that would never occur to casual spray tanner. “If you eat very acidic foods, your spray tan can smell a little bad,” she says. For those customers, Sturiale recommends a tanning formula with Aromaguard, the same deodorant used in Febreze. She also knows how to blend colors for every sort of racial skin tone. Asians, she says, have a yellow undertone to their skin, “so sometimes I’ll have to mix another solution that has a redding effect, so that they don’t look orange.” She also specializes in African-Americans, especially those with uneven or ashy skin, who can achieve, she says, with just a little spray tanning magic, “a more golden tone.”

The Picassos of spray tanning aren’t born overnight. It can take years of training to perfect your technique. Kelly Richardson, the president and owner of the B.Bronz sunless tanning company in Santa Rose, California, has been teaching workshops for amateur spray tanners since 2007. Her classes are taught “virtually every weekend,” she says, from Los Angeles and Dallas to Miami and New York City, costing anywhere from $300 to $1999.

First time spray tanners, Richardson says, usually make the same mistakes. “They spray it everywhere,” she says. “They go in a left-to-right pattern rather than a vertical pattern. They have their gun set wrong. There are a million things they do wrong.” Richardson says it doesn’t take long for even the most confident student to realize, “Wow, this isn’t as easy as I thought it was going to be.”

With an increasingly overcrowded tanning market — Richardson can still remember a time, just a few years ago, when she could count her spray tanning peers on one hand — some have found creative ways to stand out from the competition. Amie Burkholder, the owner and founder of the year-old spray tanning company BronzedBerry LLC in Stafford, Virginia, is concerned that many conventional spray tan solutions might be poisonous.

While the FDA has approved dihydroxyacetone, a natural sugar derivative that’s an active ingredient in most spray tans, Burkholder points out that it’s been approved for topical application only. “When this solution is being sprayed all over you, you’re also inhaling some of it,” she says. “DHA has just never been tested in aerosol form, so we don’t know how dangerous it is.”

She cites reports by Dr. Joseph Mercola, a controversial osteopathic physician from Chicago who has been an outspoken critic of spray tanning. In essays with scary titles like “The Hidden Dangers of Spray Tanning,” Mercola suggests that many spray tanning solutions include trace amounts of arsenic, lead and mercury. (Not coincidentally, Mercola also sells his own line of “Vitality Tanning Beds”). Inspired by Mercola’s warnings, Burkholder decided that her spray tanning company, BronzedBerry, would offer a natural alternative. She works with a manufacturer to create her own organic tanning products and solutions, made with the “least amount of chemicals possible.” Burkholder, an admitted lifelong tanning junkie, uses herself as a guinea pig, testing all of her products personally “so you know it’s 100% safe.” That, she says, is the BronzedBerry difference. Customers get a dark, realistic-looking tan, and the peace of mind in knowing that they absolutely haven’t ingested any arsenic.

If there are legitimate health concerns about spray tanning, they’re not scaring away any of Kelly Richardson’s clients. In 2010, she was contracted with the San Francisco 49er Gold Rush Cheerleaders as their “tanning advisor,” and joined them on a trip to London last October, where she was regularly told that she has “the most important job in the NFL.” During one late night tanning session with the cheerleading squad at their London hotel, the overspray of her tanning solution became so thick in the air that it set off the fire alarms. Within minutes, five hotel security officers had burst into the room, expecting a fire or worse, only to discover a room full of half-naked cheerleaders. “One of the coaches was trying to explain to the security staff what exactly we were doing,” Richardson laughs. “And due to the language differences, they thought we were ‘spray painting’ the girls. They looked at all of us like we were crazy.”

(This story originally appeared, in a slightly different form, in the June 16, 2011 issue of Bloomberg Businessweek.)