Celebrities Are Showing Off Butt Cleavage

July 25 -- With summer here and temperatures rising, your favorite celebrities are taking the art of flashing a lot of skin to new heights. Or maybe they should be described as new lows.

As reported in US Weekly magazine, the stars have been showing a lot of cleavage — and not chest cleavage, either.

Ladies of the screen and song, including actresses Natalie Portman and Tara Reid and singers Janet Jackson, and LeAnn Rimes have been spotted baring a lot more cleavage in back than in front.

"In the past, it was always about cleavage from the waist up. Now we're talking about the push-up bra for the butt," said Monika Batista, a spokeswoman for Levi's.

Lower than Low

For several seasons now, manufacturers of low-rise, rump-flattering jeans, made hugely popular in videos by singers like Beyoncé Knowles, Mariah Carey, and Jennifer Lopez, have been racing to have jeans that are the lowest of the low.

"I've known ours to be the lowest since the beginning," said Sara Sandler, spokeswoman for Frankie B. Jeans.

But a competing company begs to differ.

"We have the lowest jean on the market right now," Batista said.

The battle of the low-rise look has spawned a second fashion fad: the peek-a-boo thong.

'A Thong Thing'

"It was picked up very recently, and it's still going on, by all the celebrities — J. Lo, Pamela Anderson … " said Stephanie Solomon, Bloomingdale's fashion director.

Rebecca Apsan, thong purveyor to stars like Sarah Jessica Parker and Kim Cattrall, blames it on politics.

"I think it started with Monica Lewinsky … Everyone started talking about thongs," said Apsan, owner of La Petite Coquette, a trendy lingerie store in New York's Greenwich Village. "It was a thong thing."

It's no joke. Celebrities across the board have been seen airing their undies, including actress Gillian Anderson, MTV'S Molly Sims, model Kate Moss, and Britney Spears. But just because the stars are celebrating thong-adorned reverse cleavage, doesn't mean we can all get away with it.