On the back of her third CD, Tasty, Kelis Rogers poses in girlish white undies atop two pink scoops of ice cream the size of beanbag chairs. Inside the jewel box, she’s licking a big, round, red lollipop. In case all this was too subtle for prospective consumers, Arista at one point animated the sucker on her Web site–it moved back and forth, in and out of her mouth.

If Kelis were a teen pop-tart in training or Lil’ Kim, none of this would be particularly remarkable. But this is the woman Ol’ Dirty Bastard nicknamed Thunder Bitch. Who on her last American-released CD wore psychedelic body paint and shocking orange hair. Who had a hit with “Caught Out There,” a rant at an unfaithful lover whose Howard Dean-esque hook was “I hate! / You so much right now! / Aargh!”

Kelis isn’t a flavor of the month. She’s a talented singer with a distinctive voice that alternates between huskiness and flights into the stratosphere, more musical, with a bigger range and a better command of the nuances of phrasing and pitch than most of her peers in pop or R & B. She’s a soul singer in the old-fashioned sense of the word: capable of projecting pain, doubt, confusion, anger, and a fierce, thoroughly adult sexuality. She’s real, sometimes even frightening, in a way reminiscent at times of Nina Simone. On record, Kelis suffers real rejection, postures with real bravado, and really enjoys her power as both sexual magnet and sexual agent.

Five years ago, when her debut, Kaleidoscope, was released, Kelis and her genius producers, the Neptunes, were willing to take risks. The songs, mostly written by the Neptunes, addressed complex topics like infidelity and anger (“Caught Out There”), being in a serious relationship but not feeling ready for marriage (“Game Show”), or longing to escape from the mundane and materialistic (“Mars,” “Roller Rink”). Not surprisingly, given her emotional nakedness and offbeat glamour, Kelis’s songs from that era were popular in gay clubs, but she got major commercial radio airplay as well.

Now it seems like her adventurousness may have been partly due to naivete. She was just 19 when the album came out, and five years is at least a decade in pop-star time. In interviews Kelis routinely dismisses questions about her new image. “Times change–it’s inevitable,” she says. “I still wear the things that I like; I like to have fun with style. My attitude hasn’t changed, except I am older.”

Older and perhaps more inclined to hedge her bets. In late 2001 Virgin brought out Kelis’s second album, Wanderland, in the UK, but declined to release it in the States. (It’s still available only as an import.) Some critics have claimed this was justified, that it was a weak record; more likely it had to do with the slump the entertainment industry suffered after September 11. Maybe it was the baggy white pants and baggy striped shirt she wore on the cover. Regardless, Kelis or her handlers probably realized she might not get a third chance to play the pop sweepstakes and acted accordingly. As her image has morphed from sci-fi soul diva to sweet-toothed sex kitten, her music has become more commercially palatable. No more lyrics about outer space, no more eerie masterpieces like “Suspended,” which wouldn’t sound out of place next to Sun Ra’s “Rocket #9” on a mix CD. Now Kelis is “Rolling Through the Hood” and doin’ it “In Public” with fiance Nas.

Tasty features a star-studded lineup of collaborators, including neosoul singer Raphael Saadiq, Outkast’s Andre 3000, and of course the Neptunes. The ubiquitous first single, “Milkshake,” made it as high as number three on the Billboard pop chart, garnered Kelis a Grammy nomination, and has fueled respectable sales of Tasty, which peaked at number 27. It’s a relatively simple production: Kelis chants a singsongy, slightly naughty nursery-school style rhyme about her sexual prowess, propelled by an evil beat fuzzed out to sound like the whine of a jet airplane landing. The double entendre is annoyingly vague–what the fuck is a “milkshake” exactly? Isn’t it something only a male could, er, produce, as implied by a recent tagline on the cover of King magazine, a Maxim for black guys: “Kelis Whips You Up a Thick-ASSS Milkshake”? (Kelis poses behind the text in a skinny white bathing suit, a riding crop across her thighs.)

Casual listeners who’ve only heard the hit might be surprised by the album’s second single, the shuffling, reggae-inflected “Trick Me,” whose direct, chump-dissing lyrics are arguably more characteristic: “Freedom to us has always been a trick / Freedom to you has always been / Whoever landed on your dick….Might trick me once / I won’t let you trick me twice.” The cut is a collaboration with producer Dallas Austin, as is the more rock-oriented “Keep It Down,” a cold but polite kiss-off to casual hookups: “No thank you–I’d rather chill.” With its surging guitars, the song sounds tailor-made to be performed in a stadium. The Saadiq tracks are slower and warmer, with complex arrangements of stuttering rhythms, and sensuously intertwined vocals. The best of these is “Glow,” which is basically sophisticated music for getting it on (but enjoyable solo as well).

The problem with the record isn’t that it’s mindlessly dirty (it’s not) or even that it’s no good (it’s pretty good). It’s that Kelis seems in danger of getting lost in the mix. The Saadiq tracks sound like Saadiq, the Dallas Austin ones like nothing else on the album, and “Millionaire,” “featuring” Andre 3000, makes the singer sound like a guest on her own record.

Kelis is opening for Britney Spears on her current tour, and while this exposure is bound to win her new fans, some of her old ones are piqued. “Not cool. I can’t believe Kelis played herself out like that…it didn’t work for Nikka Costa when she opened for Britney a few years back,” read a recent post on a fan site. “I’m not paying an inflated price to sit next to prepubescent white girls and soccer moms….the average Britney fan probably wouldn’t know who (or what) Saadiq is.” Other haters responded in kind: “I LOVE Kelis and I’m very disappointed that she’s touring with Britney.” On the other hand, there was this: “Sometimes the mentality of people on this site shocks me I am going to see Kelis live when she comes to my town. I am going with several people. None of us are pre-pubescent whites. We all know who Saadiq is.” And this: “From a promotional standpoint, Kelis would be a fool to turn down the opportunity to tour with a huge star like Britney.”

By the same logic, she’d be a fool not to exploit her stunning face and body to sell records. But this is the girl who sang (on “Caught Out There”) that “It’s not / All about cash / Or how / Much you flash / How I dress is a reflection of me.” Who’s reflected in the deep V-cut gold lame bathing suit that barely contains her shakeables in the center spread of the Tasty booklet? If you wanted to be generous, you could say the outrageousness of her personal style in the Kaleidoscope era was merely an attempt to divert attention from her physical assets–there’s a look at me/don’t look at me ambivalence about many of her early publicity photos–and that the new Kelis is just a more confident, forthright, and grown-up version of the old one. Or you could boil it down, as one of her fans did, to Kelis simply wanting “cheddar/mozzarella in her bank account and a platinum plaque.” But the cheese is bait in a trap. If Kelis has compromised herself and been rewarded richly for it, what can we expect from her next time around, when the formula for success has been set and her label expects the same or better results?

Kelis opens for Britney Spears Friday, March 19, at the Allstate Arena in Rosemont. See music listings in Section Three for details.