Kelly Clarkson is decked out in black: skintight pants, jeweled stiletto-heeled boots and a blouse that plunges dangerously low. Camera-wielding fans buzz about as the singer sweeps past a velvet rope and disappears into a happening nightclub.

"OK, let's do that again," a photographer says. Clarkson and the camera-wielders back up and resume their spots.

It's midday, midweek and Clarkson is posing for photos to promote her new partnership with a brand of vitamin-enhanced water. The shoot is wedged between cutting demos for her new record and preparing for her national summer tour, which begins June 30 in West Palm Beach, Fla.

When Clarkson does get free time, she's not one to hit the clubs, she says. "I'm, like, 80 in my mind," says the spunky 24-year-old, who talks like an auctioneer on caffeine. "My downtime is literally downtime."

It's been a whirlwind four years for the pop star, who became instantly famous in 2002 when she won the first "American Idol" title.

Clarkson's debut album, "Thankful," earned double-platinum status, and her multiplatinum follow-up, "Breakaway," netted two Grammy awards this year. She's now at work on her third album, due in early 2007.

"It's like a throwback to Janis Joplin, Sly; some of (the new songs) are a little Prince-ish," Clarkson says of the new work. "It's still got the whole rock-pop vibe, but it's kind of got certain songs, too, that have an extreme amount of soul in them as well."

The actual assembly of the album will have to wait, though. Clarkson is about to embark on her Addicted summer tour.

"People are going to be floored," she says, declining to reveal any details. "It's a more musical show, like I always do, but the things we're bringing in, like all the video stuff and different things, are major ones."

Clarkson plans to perform tracks from her forthcoming record, where she "explores a more straight-ahead rock side," says her manager, Jeff Rabhan.

"This definitely is going to be the biggest show she's ever done, in terms of audience and production," he says, "and Kelly's going to do what she does best, which is knock the vocals out of the park."

Before the tour starts, Clarkson has obligations to tend to — like this day's photo shoot. She joined forces with Glaceau's vitamin water to promote her favorite flavor ("Focus, the pink one."). Clarkson is also involved with the company's "vitaminschool" program, in which high-school students prepare healthy meals for a chance to win a $100,000 scholarship. Clarkson was one of four judges who helped choose the winner Thursday in New York.

With her success, she says, she feels she wants to also focus on work that helps others.

"I've done well enough to where I'm fine for the rest of my life," Clarkson says. "So my whole goal now is I just want to be part of things that are positive and make a difference."

Clarkson works with the Susan G. Komen Breast Cancer Foundation. She'll donate a portion of her Addicted ticket sales to the foundation's Race for the Cure initiative.

Adjusting to overnight fame has been "pretty hard core," Clarkson says. "Normal" outings, like going to the grocery store, are a thing of the past. Even a wig and glasses don't help.

"People notice everything. They notice my chin," she says. "Three hundred sixty-three days out of the year, I'm fine, I love it. It's hard, but at the same time it's a blessing."

She's also learned to set some limits and take time off. But not enough time to date, she says. Clarkson is single and says she'll probably stay that way for a while. "I give up. Is that bad?" she says. "It's just too hard. It sounds so cliche to say 'I'm too busy,' but I really am."

And as the photographer beckons Clarkson, a stylist carefully smoothes the pop star's hair and she walks off, back to the "nightclub" and the flashbulbs.