On a recent visit to his home high in the Hollywood Hills, Mars, 27, looks dressed less for success than for hiding from it. In rumpled jeans and an untucked T-shirt, his eyes shielded by silver aviators, the usually dapper entertainer is due to fly to Sweden to promote his new sophomore disc. At the moment, however, he hardly seems in the mood to talk himself up.

"If people are going to have an idea of me," he says, "I'd just want them to think of a guy who goes in the studio, works hard and jams out."

, released last month, gives a different impression of the man behind the choreographed moves, presenting a dramatic vision of love under siege by fame ( ), fortune ( ), and his own tomfoolery ( ). Even relatively conflict-free tunes such as and - in which he invites a "dirty little lover" to bang on his chest like a great ape - exude a gritty desperation.

It's an unexpected shift in tone from an artist known initially as pop's go-to good guy, an old-fashioned romantic doling out positive affirmations not long after he'd first appeared on B.o.B.'s and Travie McCoy's . "I think people will be surprised by it," says Philip Lawrence, one of Mars' partners in his Los Angeles-based production crew, the Smeezingtons. "But it's not for shock value - it's telling a story, digging deeper into the feeling of what it means to become a celebrity."

Speaking in a relaxed manner the opposite of his frenzied stage presence, Mars describes that experience as "being thrown to the wolves and having to deal with it", and says he wants to reflect where he is, not where he was.

"I love those [older] songs," he says, sunning himself on a patio. "I'll stand by them and sing them till the day I die. But an artist has to stay excited to keep on doing it. And the way to stay excited is to keep pushing and experimenting. I feel like I pushed on this record."

So far he hasn't seen any push back: the album entered Billboard's album chart at No2, while , the disc's lead single, spent several weeks atop the Hot 100. Reviews have been strong too, with high praise from and , which says the album "makes the competition sound sad and idea-starved by comparison".

Indeed, the songs on burst with detail, each one meticulously constructed. In , Mars and his mates recreate the sharp-angled reggae-rock of the early '80s Police; is a lush disco-soul jam; and channels Sam Cooke's church-born R&B. The infectious sonics soften the effect of edgy themes such as the homage to a stripper named Where Your Stacks At in . And they provide a buoyancy that, as in so much great pop, lifts Mars above the sometimes-bleak scenes he describes. (The Smeezingtons were behind the endearingly acidic Cee Lo Green hit known on the radio as .)

"One of their great talents is that they have this fun, light vibe in the studio," says Jeff Bhasker, who along with Mark Ronson joined the Smeezingtons for production and songwriting work on . "That allows you to be free so that you can let that primal emotion come out without being embarrassed. Then they polish afterward."

Part of that polish, Ronson says, is the charisma Mars has honed since his childhood days as an Elvis impersonator in Hawaii, where he grew up. "Everything Bruno adds is what takes it into superstardom," says the producer, who recalls being impressed by Mars' performance in a tribute to Amy Winehouse at the 2011 MTV Video Music Awards (Ronson co-produced Winehouse's album.) "If you put any other singer over it wouldn't be one of the most impactful songs of all time, and the same is true with ."

Whether or not lives up to the work of Michael Jackson, Mars says he longs for the pre-digital era when acts such as Jackson and Prince retained an air of mystery.

"Don't you love it that Prince doesn't use Twitter?" he asks. "Don't you think that he's somewhere on a unicorn?"

Then he admits he wished he hadn't "wasted" a title he used for his first EP: it was called .