A new trend is jutting out above low-rise jeans and below midriff-baring tops.

Pelvic bones, not particularly known for their sex appeal, are the latest must-show body part among flesh-flashing stars like Cameron Diaz (search), Pink and Pamela Anderson (search).

“I live in L.A. and I see it on the streets,” said E! fashion director Elycia Rubin. “Britney has it a little bit, Cameron a lot, Janet Jackson too. There’s a certain sexiness about seeing that bone.”

Punky pop star Pink (search) may have the boniest bones of them all, which she proudly reveals in her videos for “Just Like a Pill” and “Family Portrait.”

Spears and Anderson have been flaunting their nether regions in various low-slung fashions. And Diaz, super fit from training for her kick-butt role in Charlie's Angels: Full Throttle, has been displaying her bones in sexy pants on the movie's promotional tour.

Of course, everybody has pelvic bones, but most people conceal them with a cozy layer of meat.

Gunnar Peterson (search), personal trainer to J-Lo, Ben Affleck, Lucy Liu and other A-listers, said protruding bones are a sign of “very low body weight.”

“As a rule, we store fat at the center of our bodies. If you’ve lost that much body fat, you’ve lost a substantial amount,” he said.

Peterson is careful to make clear that a visible, V-shaped pelvis is not necessarily a sign of ill health — but says it is at the “lower end of natural.”

“If they are protruding, you’re either genetically very lean or at the low end of what is acceptable," he said. "You couldn’t have much lower body fat without courting illness.”

The body needs a certain amount of body fat to maintain a healthy immune system, reserve storage for energy and protect reproductive and internal organs, Peterson explains. Very low body fat has also been linked to amenorrhea, osteoporosis and eating disorders.

And if you’re among the masses who sit at a desk all day, good luck achieving the skeletal look even if you want to, Peterson said.

“It takes working out at a high and consistent level — it’s not your three hours a week with your trainer and slacking off on the weekend," he said. "It takes a conscious effort, incredible commitment and stamina."

Rubin, a fan of the trend, thinks the look is more about fitness than famine.

“You don't have to be anorexic — you can still have a little bit of meat on your body and see that bone,” she said. “Some people have it hereditarily, but most people need to really work out to get that."

But Boston College sociologist and body image expert Sharlene Hesse-Biber (search) said the bones are the latest focus of an ongoing “fairest of them all” contest among Hollywood stars.

“It’s a competition between celebrities to push the envelope," she said. "Their trade depends on being out there doing something new and different, and this happens to be a new thing. It has to be an ideal that’s unattainable, because if it were attainable it wouldn’t be desirable."

Impressionable fans then get into a monkey-see, monkey-do race with the stars they want to emulate, which can have dangerous repercussions, Hesse-Biber said.

“People with low self-esteem are more likely to be influenced by magazine photos — we know that from research," she said. "There is increasing body dissatisfaction among young people, which leads to dieting and binge eating."

While Peterson thinks Diaz "has a great body," he said in real life, people are often happier with a little meat on their bones.

"If you're 15 pounds overweight and comfortable with that, you're farther ahead in the overall race of enjoying life," he said.