Billboard Cover: Behind the Scenes With Katy Perry as She Rehearses for the Super Bowl -- 'The Biggest Event of My Career'

Backstage at the top-secret rehearsals for the biggest gig in American showbiz, in a large, stuffy room marked "Wardrobe," a dozen or so half-naked female dancers wriggle into candy-colored, body-hugging costumes and pull on matching socks and sneakers. At the center of the action is Katy Perry, lying belly-down on a massage table with one bare leg poking out from under a blanket -- simultaneously getting treatment for a bad hamstring and giving notes on her dancers' and bandmembers' costumes. "It's obscene, I know," Perry says, referring to her elaborate multitasking. "But it's not because I'm a diva!"

It's hard to argue with her -- after all, she's a busy woman. In less than two weeks, on Feb. 1, Perry will take the stage at Super Bowl XLIX's halftime show, singing and dancing her way through 12-and-a-half painstakingly choreographed minutes of blockbuster hits for a TV audience of about 100 million (not to mention the 63,400 fans packed into Arizona's University of Phoenix stadium). To get the show in shape, Perry and her team set up here at the Los Angeles Memorial Sports Arena, where they prepped her ongoing Prismatic Tour last spring. It's a massive undertaking. Longtime manager Bradford Cobb compares the endeavor to launching an entire tour. Perry agrees: "This has had brainpower going into it from before we knew we had it, when we were being courted."

Perry weighs in on everything from shoe options to zippers versus velcro, and whatever the question is, she has an immediate, decisive opinion and the confidence that her team will make it happen. "I used to say, 'That's ridiculous, we can never do that,' " says Baz Halpin, her longtime co-creative director. "Now I just say, 'You want to fly in on a giant banana and burst into flames? We'll make it work.' "

As Perry surveys the dancers, she's surrounded by the fashion designer Jeremy Scott (who created Perry's Super Bowl costumes), her stylist Johnny Wujek and a woman whose entire job is adding "bling" to the wardrobes -- which Perry is generally inclined to do. When one dancer appears, Perry notes the fit of her top, which may be risque for the family-friendly Super Bowl. "Your boobies are a little too much for that," Perry says cheerfully. "Show Sarah!" (She's referring to Sarah Moll, who runs halftime for the NFL, and whose facial expression shows that she agrees with Perry.)

If Perry is nervous, it doesn't show. She's already 108 shows deep into the Prismatic Tour. Most halftime artists use the performance as a mega-sized launch pad for whatever they have up next, but Perry says it will serve another purpose for her. "There isn't any selling point going up the day after," she says. "I'm just selling my music to the broadest, widest audience ever."

With her 2010 blockbuster Teenage Dream, Perry ascended to the top tier of pop, scoring a Michael Jackson-rivaling five No. 1 Billboard Hot 100 singles and selling 2.9 million copies of the album, according to Nielsen Music. The 2013 follow-up, Prism, sold 1.6 million, and featured two No. 1s ("Roar" and "Dark Horse," with Juicy J).

Still, it's hard to imagine the sales gap didn't stoke Perry's competitive spirit, especially as a new wave of female stars from Ariana Grande to Iggy Azalea began chewing up radio spins. Pop fans tend to pit female stars against each other: Madonna vs. Lady Gaga, Gaga vs. Perry, and lately, Perry vs. Taylor Swift. That last beef has been fought through magazine profiles and subtweets without either explicitly naming the other. In 2014, for instance, Swift described a fellow female musician as her "straight-up enemy" who tried to "sabotage [Swift's] entire arena tour." The next day Perry tweeted, "Watch out for the Regina George in sheep's clothing," a reference to Mean Girls that everyone took to be about Swift. Asked about it now, Perry only says, "If somebody is trying to defame my character, you're going to hear about it."

In any case, the Super Bowl gig is a major win in the Perry column. And not the only one: In 2014, she sold out more than 80 arenas, grossing more than $146 million, according to Billboard Boxscore, making Prismatic the biggest tour of the year by a female artist. Likewise, "Dark Horse" was 2014's No. 1 song on the Mainstream Top 40 chart, and she still has the most Twitter followers -- more than 64 million -- of anyone. "Watching the rehearsals solidified our feeling that she's the right choice," says the NFL's Moll. "And we see the connection she has with her audience and her reach on social media." Says Charli XCX, who will be opening for Perry this spring: "She makes sugary, plastic pop so well, makes it sound smart and amazing. But she also has such a vision within her videos and her live show. I love that she goes all the way with it."

When she's working, Perry wakes up around noon, after at least nine hours of sleep. She checks The Huffington Post to see what's going on in the world and slips into the uniform she has worn for the last year: a black Adidas track suit with white stripes and matching slippers. The effect is half Run-D.M.C., half Olympic Village. But style isn't the point. "I'm just not playing the picture game," she says, referring to paparazzi. "If I wear the same thing every day, the pictures don't sell."

Today, with the wardrobe meeting done, Perry curls up on the floor of her dressing room, which is stocked with water and fruit, a burbling humidifier and a pair of beige sofas. She's wearing a gold nose ring, pink nails and lipstick, and her hair pulled back in a casual ponytail. Butters, the puppy she adopted in 2014 (she looks like a living teddy bear), comes flying in, carrying a soggy ball. Perry recently gave custody of Butters to her longtime assistant, Tamara, and her girlfriend. "I was going through a breakup and I was like, 'I'm going to get a dog!'" Perry says, referring, presumably, to one of her off-again stints with John Mayer. "But honestly, I have to run an empire, and as much as I love animals I don't know if I have the mind capacity to do it."

The rest of her early-afternoon routine involves physical therapy for her knees and some massage, acupuncture or cupping. "Sometimes I get a steam for my voice," she says. She also has a therapist she sees when she's in Los Angeles. "That's one of only a handful of people who see me as Katherine Hudson," Perry says, using her real name, which she changed to avoid confusion with the actress Kate Hudson.

Perry lives in what she calls "a compound" in L.A. with her older sister, Angela Hudson; Hudson's husband, Svend Lerche; and their baby. Her younger brother, David Hudson, lives nearby in Los Feliz and her parents, Keith Hudson and Mary Perry, are in Irvine, Calif. "Everybody is somewhat close," she says. "I always dreamed of living commune style. I want my own Neverland ranch at a some point, but not with the salacious parts." She cracks up.

Her dream? "My own Starbucks on the property," she says, only half-joking. "I have to create my own world because it's hard to go into the other world sometimes. Barbra Streisand has a mall downstairs in her basement -- just weird, amazing stuff like that. I get it, because it becomes such a thing to go out in the world."

One of those times came in early January, when she was spotted at dinner with Mayer in L.A. (The pair have dated at least twice since 2012. She also was married to Russell Brand for 14 months starting in late 2010 and was reported to have been dating Diplo last year.) She declines to define their relationship, bristling at the question. "What I will say is that to have any relationship at this level you have to just be protective and figure out how to navigate it," she says. "There is no handbook." She thinks about it, and adds, "In all my relationships, I've learned how I have to be more careful and that it's not up for public consumption."

Perry's parents were hippies-turned-Evangelical ministers, home-schooling Perry and her two siblings and raising them according to a deeply conservative, fire-and-brimstone belief system. The family, who lived mostly in Santa Barbara, Calif., was poor enough that food wasn't always easy to come by. "But I love my childhood," she says. "Because I can't change it and it made me who I am." Perry regrets her lack of formal education, and stays informed about news and issues that are important to her, including her outspoken support for LGBT rights. "I grew up in a little bit of a bubble of ignorance and judgment," she says. "And so I'm happy that I've been able to evolve past that."

At 13, Perry convinced her parents to bring her to Nashville to seek a career as a gospel singer; she released an album on a Christian label at 16. But after discovering secular artists, from Queen to Gwen Stefani, she moved to L.A. and shifted her ambitions -- first aiming to be a acoustic guitar-wielding singer-songwriter, later settling on her current plan: global pop domination. She bounced from contract to contract -- "I had two cars repossessed, I was always going by the hair of my chinny chin chin" -- before landing on Capitol Records. Working with Dr. Luke, Max Martin and Benny Blanco, she broke through with 2008's button-pushing "I Kissed a Girl." Since then, that core team (often helped by songwriter Bonnie McKee and others) has produced a string of No. 1 songs. "My strengths are melodies and lyrics," Perry explains. "Max is the king of melodies and Luke is the king of, like, sounds. When we get together we make the biggest songs."

"Everyone has been asking me if I'm going to be nervous before the halftime show," Perry says. "I'm like, I'm f---ing human. This is the biggest event of my career." To prep, she has been studying recent shows, with extra attention on Beyoncé in 2013 and Madonna in 2012. "Those performances are clean and streamlined," she says. "They're about the catalog, the songs. I like Madonna for the graphic effects she brought." And Beyoncé? "She brought so much strength, so much sassiness and just the right amount of sex," Perry says. "She's an icon. Elvis, The Beatles, Michael Jackson -- she's in that category. I'm not. She's like five notches above me, and those levels are compounded in difficulty."

She also reached out to Bruno Mars, a buddy from awards shows, who had the halftime gig in 2014. (She insists she doesn't have many close celebrity friends -- she's probably tightest with Rihanna, Adele and Ellie Goulding.) She scans the email on her phone -- "let me just make sure it's kosh" -- before reading it out loud:

Hello, exclusive Super Bowl club member! I was wondering if you are in L.A. at all this month and would have tea with a sister who is about to throw up with nervousness re: [football emoji]. I've heard about your process through our managers, but am wondering if you had more insight on important things like, spray tan the night before or three nights before? JK, or maybe not!

"I'm going to meet up with him and he'll tell me whatever there is to tell," Perry says. "Although I don't know how much there really is." She knows that no matter how much she prepares, the halftime show is live, and as Janet Jackson and M.I.A. demonstrated, anything can happen. "You can't control other people, and hopefully they're on the same path with you," she says. "My special guests" -- including Lenny Kravitz -- "don't have any agenda other than the music. But you can never be too sure." Kravitz claims that he and Perry have been cooking up a surprise. "It's cool because it's different for me," he says. "Our voices are going to blend well together."

Perry's focused on the opportunity: Playing for an audience so vast that it will include some of the few remaining human beings who have never heard of her. What's her strategy to win them over? It's simple, Perry says: "I want the show to be quintessential Katy. It's like the exclamation point on the whole last cycle. This is the cherry on top of everything I've already done."