Bruno Mars delivers loose, spirited show at Cosmo’s Chelsea theater

Sure, but he had a request as well.

“Any song in the world,” he challenged the audience to yell up on his opening night in the new Chelsea theater at The Cosmopolitan of Las Vegas. “I just want to play around. Any song in the world …

“Except for my songs.”

This came after a freewheeling late-night set had the band — through events that seemed to make sense at the time — plunking out an impromptu cover of TLC’s “Waterfalls.” When it came time to deliver the signature midsection rap, Mars coaxed one of his band members up to the mic. He nailed it, to the great delight of the star attraction.

“That’s the best $200 I ever spent!” Mars declared, no doubt voicing the opinion of everyone in the packed house — at least those who knew better than to expect a buttoned-down, structured arena showcase of hits.

Billboard’s Artist of the Year and his irresistible eight-piece band, The Hooligans, announced their intentions from the get-go.

“We aren’t on tour, we haven’t played a show in a long time. This is for us tonight,” Mars announced to a general admission floor that had waited as long as two hours for the show to begin at 11 p.m. Sunday.

This was after the opening blast of Prince’s “Sexy M.F.” set the tone for a very Prince-like 90 minutes, a superjam of R&B classics and roughed-up versions of Mars originals.

A three-piece horn section made Mars’ slicker studio hits such as “Treasure” and “Runaway Baby” sound like old-school funk jams from the ’70s. Six of the eight Hooligans would slide around the stage or lock into formation behind the singer (the poor keyboard player and drummer having to stay seated).

The liveness of it all was quite the contrast to the other big star of the Britney/Bruno weekend, though Britney Spears was in the Mars audience for at least the first half of the show — hopefully taking notes.

At one point, Mars turned his back on the audience to have the tech crew show him all the lighting formations that could be displayed on his translucent, geometric stage design: “Surprise me. Shock me right now. What else you got?”

It was miles away from Spears’ locked-down dance show, but business as usual for the 28-year-old Mars. Even in the sports arenas, he was throwing down his mix of the Barrett Strong oldie “Money” and his Travie McCoy collaboration “Billionaire” at the MGM Grand last August.

This night added a Michael Jackson medley of “Billie Jean” and “Dirty Diana” by way of the intro to Nirvana’s “Smells Like Teen Spirit.”

And this from an entertainer with such mainstream radio appeal, he had young children in the audience of an 11 p.m. show.

For fans perhaps not accustomed to such looseness, Mars obliged them with a sincere piano- and organ-backed rendition of “When I Was Your Man” (“That was my one serious song for the night,” he declared) and straight-ahead versions of “Marry You” and “If I Knew.”

Still, the Super Bowl-bound star seemed to feed on the spirit of the eight-show deal he signed to perform in the relatively cozy new Chelsea. At least two-thirds of about 3,100 fans were standing in front of him, with the others parked in horseshoe rows of theater seats above.

Mars referenced his childhood in a family band, playing covers “every night ’til 1 in the morning.” To prove it, the band proceeded to mash up Led Zeppelin’s “Whole Lotta Love” with “Your Love,” the ’80s hit by The Outfield.

The band is back for a New Year’s Eve show at 11 p.m. today.

Two years ago, Stevie Wonder had some of his Cosmopolitan audience defecting to the outdoor patio to watch the fireworks on the Strip. But if Mars’ Sunday night/Monday morning excursions into Bell Biv Devoe’s “Poison,” Bobby Brown’s “Every Little Step” and Montell Jordan’s “This Is How We Do It” sound like the night’s biggest party to you, then the fireworks may just have to wait until next year.

Contact reporter Mike Weatherford at mweatherford@reviewjournal.com or 702-383-0288.