WE’RE JUST CAVEMEN, hitting on rocks,” says Bruno Mars. “It’s no different—you’re a caveman and you got a rock in front of you, you hit it with a stick to get everybody dancing. This is our time to forget about everything, it’s joy time. So who’s the best at hitting that rock? Who’s going to make the village dance the hardest?”

At a casual glance, you might not know that Mars is one of our superstar cavemen. Pulling up to an upscale Italian restaurant on an anonymous street in L.A.’s San Fernando Valley, alone in a relatively modest Cadillac, he parks in back by the dumpsters to slip in quietly. In contrast to the flashy outfits he wears onstage, he’s dressed in a simple collarless bomber jacket, a white Gucci logo T-shirt and camouflage pants. A small crucifix on a thin chain hangs around his neck.

But at age 31, the singer/songwriter/producer dynamo born Peter Gene Hernandez is unquestionably one of the most highly decorated figures in pop music, with 21 Grammy nominations and 21 Hot 100 hit singles. He has sold over 170 million singles and 26 million albums worldwide and notched his first five No. 1 hits faster than any male artist since Elvis Presley. His third album, 24K Magic, debuted at No. 2 in November; more than two months later, it was still parked in the top five.

On this drizzly January day, Mars is trying to take care of business before heading to Japan for promotional duties. He’s finalizing plans for the album’s second single, the breezy, drop-top banger “That’s What I Like,” and plotting out his performance for the Grammy Awards. Today, he’s mostly bouncing between meetings and calls to assemble the staging for his massive world tour—already more than 100 dates this year, starting in late March in Antwerp, Belgium, and hitting the U.S. in July.

“I want the show to be powerful, because people spent some money on a ticket,” he says. “I’ve seen some awesome shows. I’ve seen Prince and Michael Jackson ; those are nights I will remember forever. I’m not doing my job unless I leave a piece of me everywhere I go—if you do the right show, it will stay with people and they’ll tell their kids about it. I hope people can see what I was feeling when I made the records. Then I want to go beyond their expectations and fly.”

With his old-school dedication to entertaining and his grounding in classic pop and R&B songwriting, Mars stands alongside Adele as one of today’s most universally beloved musicians. “My mum loves Bruno Mars and my son loves Bruno Mars and he’s 5,” says James Corden, host of The Late Late Show—and, recently, the Grammys—in a phone call. “I love how joyful, positive, uplifting his music is. It excludes no one. Everybody is welcome.”

Mars makes no secret that being onstage comes much easier to him than being in the studio. Almost four full years passed between his quadruple-platinum Unorthodox Jukebox album and the release of 24K Magic. He works so obsessively on each song, he says, that he drew up parameters for himself in order to get the concise, nine-song project finished. “I wanted to make a movie, where each song has its own moment,” he says. “So ‘Versace on the Floor’ is the tender moment, ‘That’s What I Like’ is the fun moment, and the ballad at the end [“Too Good to Say Goodbye”] seals the deal. That’s how I kind of tricked myself into making the album.

“We were trying really hard to tap into the ’90s R&B music that we grew up with, and it’s a very fine line—it can get tribute-y, it can sound forced,” Mars adds. “But that New Jack Swing sound brought me so much joy as a kid, so we took that on and did our best to try to get that feeling, that effortless fun.”

His interest in exploring the sounds of the past has sometimes led to accusations that Mars is just a talented copycat. When 24K Magic was released, one publication offered a track-by-track analysis of which artist each song was imitating. Not surprisingly, Mars gets heated about such criticisms.

“Man, that pisses me off so much!” he says. “It’s so easy to say that, but anyone that does that kind of shit has never written a song in their life. That’s why I’m here, because of musicians before me.

“Don’t get me wrong—there is plagiarism when you just say ‘Hey, man, what are you doing? I’ve heard that already.’ And I’m not stupid, of course it sounds like [the ’90s]. We’re using these vintage instruments and there is a certain sound, but it’s not just regurgitated. You can tell that we were listening to ’90s R&B. It has that spirit. That’s what we capture, and that’s what I want.”

Every time I think about it, my whole story is just weird,” says Mars. “Even I don’t get it!” He was born and raised in Honolulu, one of six children—his Filipino-Spanish mother was a singer and dancer; his Jewish–Puerto Rican father was a percussionist. By age 4, young Bruno (the nickname came from his father, who thought the infant Peter resembled wrestler Bruno Sammartino) was performing five days a week in the family band, the Love Notes, singing Michael Jackson and Temptations covers.

According to his older brother, Eric “E-Panda” Hernandez, when Bruno was just a few years old, his parents dressed him up as Elvis for Halloween. “He was already so in tune with Elvis that he was imitating the moves, the lips, drawing a crowd,” says Hernandez. “I thought, ‘Holy cow, he’s a showstopper already!’ ” “Little Elvis” went on to perform at halftime in the 1990 Aloha Bowl and had a cameo in the 1992 film Honeymoon in Vegas.

“If you took your kid to school with you every day, and you were studying rocket science, he’d probably be a rocket scientist,” says Mars. “So that’s just it—my dad and mom took me to work every single day, and I got to see what it’s like to entertain an audience. I got to entertain everybody who came to Hawaii—a roomful of people that didn’t speak English, from around the world—and to see what music can do, and how it can bring the world together.”

Above all, he learned the power of a great song, the fundamentals of writing music that far outlives its creator. Hernandez, who is now the drummer in Mars’s band, recalls Bruno constantly studying music videos—doo-wop, Michael Jackson, Elvis, anything he could get his hands on—in the bedroom they shared.

“I’ve been singing amazing songs since I was a kid,” Mars says. “They weren’t my songs, but they were classics. So I’ve trained my brain to know what it feels like to sing an amazing song—when you do a lot of covers, you see it; you’ll play a song and you see everybody freak out when you get to that chorus, everyone is singing. It taps into something, whether it’s nostalgia or it just makes people feel a certain way.”

His father gave him a guitar and started teaching him to play—surf music at first, classics like “Walk Don’t Run” and “Apache.” The influence ran deeper than just the music, as evidenced by the silk-shirt-and-shorts set, white shoes and gold jewelry he sports on the cover of 24K Magic. “The style stuff all comes from watching my dad—the pinkie rings, the pompadour, everything,” Mars says with a big grin. “My dad would take me to school in some big, busted-up Cadillac, and he’d be wearing a rhinestone jacket and have his hair all whipped and greased up, flashy glasses, and I was like, My dad’s not like the other dads at school! I’d try to get out of the car, zoom out. And now I’m the one driving the busted Cadillac, wearing some gaudy shit, and it’s what makes me happy.”

“Bruno is a fashion leader, with a sense of style that is truly his own,” says Tommy Hilfiger, whose clothes Mars sometimes wears onstage. “He is almost chameleonlike—for one concert, he’ll wear an animal-print shirt, then the next, he’ll be in a tuxedo, and it’s all him, he is totally in control of his presence.”

After graduating from high school, Mars moved to Los Angeles to pursue a musical career. (He now lives in the Hollywood Hills with model/actress Jessica Caban, whom he has dated since 2011.) He was signed by Motown Records in 2004 but then dropped. He kicked around town, signing a publishing deal, playing in cover bands and soaking up all he could from sympathetic, successful songwriters. He wrote songs for K’naan, Brandy and Flo Rida and, in 2009, co-founded a production team, the Smeezingtons.

His breakthrough came with the hits “Nothin’ on You” by B.o.B. and “Billionaire” by Travie McCoy, both of which featured his voice on the hooks, and then with Cee Lo’s 2010 smash politely known as “Forget You.” Just weeks before that song dropped, Mars released “Just the Way You Are,” the first single from his debut album on Atlantic Records, Doo-Wops and Hooligans. The irresistibly sweet ballad went to No. 1 and topped the adult contemporary chart for a record-breaking 20 weeks. (The next single, “Grenade,” also went to No. 1, and the ukulele-driven trifle “The Lazy Song” cracked the top five.) After a brief tour opening for Maroon 5, he played headlining dates for more than a year, as the album saw sales of more than six million units worldwide and an unbelievable 300-plus weeks on the Billboard Top 200.

On the road, though, Mars became aware of the limitations of his repertoire. “The first album was so ballad-heavy,” he says, “and when I toured I was like, ‘Man, I need to dance!’ We gotta pick this up, because we can offer more and we’re kinda stuck. And that’s where ‘Locked Out of Heaven’ and ‘Treasure’ and a lot of tunes on the second album came from, because we wanted to push the tempo.”

With an Anglo-reggae groove reminiscent of the Police (Mars and Sting sang together at the 2013 Grammy Awards), “Locked Out of Heaven” shot Unorthodox Jukebox out of the gate in 2012. The album explored disco and classic soul styles and topped charts around the world. And then, at the end of 2014, Mars was featured on producer Mark Ronson’s earth-quaking, booty-shaking, record-breaking throwback “Uptown Funk.” Certified diamond, for sales over 10 million, the song is only the eighth single in history to spend at least 14 weeks at No. 1. “Uptown Funk” won three Grammys, including record of the year, and for months it was unavoidable—on your TV, in your car or at sporting events.

Mars says the song emerged only after a long struggle and that they had almost tossed it away. “We went through some trials and tribulations,” he says. “I’m not lying when I tell you that we were fighting—I was on tour and Mark would send me something and I’d be like, ‘Are you out of your mind?’ And I’d send him something back and he’d be like, ‘No, my version is better.’ We were both fighting for the greater good of the song.

“You press play and it went, ‘This here’s that ice-cold…’ and it was like, ‘Oh, what’s about to happen?!’ But then ‘Oh, man, that’s what you got? Nah, never mind, turn it off.’ And that kept happening for months.

“Finally the solution was that we just needed to dance—to say, ‘Don’t believe me, just watch,’ and that’s it. Don’t try to write a hook. You don’t need more; that already said everything. But it took us a while to feel that, because the way we were doing it was so unorthodox, piece by piece. When we finally got together and picked up the instruments, we got to feel it. That’s when the superpower comes in.”

Even after cranking out so many hits—plus collaborations with and writing efforts for everyone from Lil Wayne to Alicia Keys, Adele to Jay Z and Kanye West—Mars has no formula or shortcuts; songwriting remains an instinctive craft.

“When you’re in the studio, you can feel the energy shift,” he says. “It’s no different from telling a good joke—you can tell when it lights up the room. Or from telling a shitty joke that makes everyone want to leave and you hear the crickets. So you’re always trying to find that magic and then capitalize on it.

“You find something—‘put your pinkie rings up to the moon’—and everyone’s excited, but now what? What does the bass sound like, or the drums? If ‘24K Magic’ is supposed to sound like I’m having the time of my life, you gotta hear me smiling on the record.”

There’s no bigger stage than the Super Bowl halftime show; Bruno Mars is one of a few performers who have played it twice. In 2014, he played during a rare northern excursion, as the 48th annual game took place in New Jersey. “Rehearsing in the cold sucked,” he says. “We got lucky on the day, it was 50 degrees, but two days before it was -9 or something.” His action-packed performance was the highest-rated halftime show ever (since surpassed by Katy Perry and Lady Gaga) and earned widespread raves, especially considering that his career hadn’t quite reached the spot’s usual mega-A-list status.

Then last year, on the heels of “Uptown Funk,” Chris Martin of Coldplay invited Mars and Beyoncé to join the group’s halftime set. “I told Chris, ‘This is your Super Bowl performance, you deserve it, go kill ’em,’ ” Mars says. “But he’s such a sweetheart and he kept saying, ‘Bruno, this is a gift I want to give to everybody.’ He talked me into it. He’s a sweet talker, that guy. And she signed up, and all of a sudden I’m in rehearsal dance-battling Beyoncé—what the hell happened?”

Mars is proud of his work ethic and dedication to every appearance, something Corden can attest to after they filmed a Carpool Karaoke segment last year (the clip has had nearly 40 million views on YouTube since airing in December). “My biggest memory of that day was that the second it ended, I got a little depressed,” says Corden. “Like the last day of vacation, where you’re on the plane home and feel sad that it’s over. It was so euphoric, I just wanted to do it again. There’s a moment at the end of ‘Uptown Funk’ where we’re just sitting there and breathing heavily, and that was real. His commitment was everything—we left it all in the car.

“I think he’s 100 percent on his way to being one of the greats,” Corden continues. “There are great showmen who get by without always having great songs and great songwriters who aren’t great showmen, but he’s both those things. He has this unquantifiable energy, where you want to watch it and be a part of it somehow.”

Hernandez notes that his brother works tirelessly, showing up for every sound check, sometimes arriving before the rest of the band. “He sees something lacking in the business, maybe something we were influenced by as kids that’s missing today, and he sticks to his vision,” says Hernandez. “He’s put that work mentality on the rest of the band, where he makes us want to be great.”

The rain has stopped and as the sun goes down over the Santa Monica Mountains, Mars heads to the restaurant’s back patio for a cigarette. He seems in no great rush to get back into the scramble of preparing for a tour and keeping the business humming. With the long process of an album finally complete, he says that although he’s open to the idea of more new music or another collaboration, he wants to be careful.

“I just don’t want to feel gross,” he says. “It’s as simple as that. I don’t want to feel gross, I don’t want to regret any decisions. Even if I turn down a sweet check because I don’t want to be on that billboard, hawking some shit to the world—I just don’t need to do that. Because you get one shot at this.

“I’m not a model. I’m not an ice skater. I’m not a chef. I’m here to do music. And I want to be able to look back and say, ‘Yeah, I did it the way I wanted to do it.’ Whether it triumphs or fails, I can live with that.”