Aspiring model Ali Lohan was a startling sight when she stepped out in Hollywood this week, and RadarOnline.com has shocking photos of her latest weight loss crisis, which has sparked numerous nutritional experts to suspect she has an eating disorder.

At 5’8 1/2”, Lindsay Lohan’s little sister appears to be less than 100 pounds, Hamptons Diet creator Dr. Fred Pascatore exclusively told RadarOnline.com.

Once boasting healthy curves and a youthful glow, Rumer Willis’ weight has recently plummeted, sparking concerns that she has health issues like her mom Demi Moore, and RadarOnline.com has photos of her startling slim down.

“She appears to be about 105 pounds now, it is an unhealthy look and her clothes are heavy looking and hanging off her,” The Hamptons Diet creator Dr. Fred Pescatore, who has not treated Rumer, tells RadarOnline.com in an exclusive interview.

Angelina Jolie doesn’t normally have to fight for the spotlight, but her bizarre behavior at the Oscars that involved her flaunting her emaciated figure in a high-slitted gown is a cry for attention, an expert tells RadarOnline.com.

“People often flaunt their bodies in need of attention,” psychotherapist Jessica Aronson, who has not treated the star, told RadarOnline.com in an exclusive interview. “Her dress, like many others such as Jennifer Lopez’s, was so exposing and in my clinical opinion a deeper desire for attention."

Just 24 hours after being spotted looking alarmingly thin, Macaulay Culkin bailed on his monthly DJ gig at Le Poisson Rouge in New York City.

Instead of a live appearance, Culkin dropped off an ipod with his playlist, and put out a box to collect canned goods in exchange for free admission.

It was a troubling development in light of Culkin's recent appearance -- which had everybody talking.

Macaulay Culkin captured the hearts of millions as the cute kid in Home Alone, but the 31-year-old actor is now striking fear into the hearts of his fans with his startling weight loss, and RadarOnline.com has evidence of his horrific transformation.

In images obtained by Entertainment Tonight, Culkin was snapped looking pale and gaunt in New York City on Wednesday when he stopped to sign autographs for fans, while drinking the energy drink Red Bull.

Where has all Zoe Saldana’s muscle gone?

The actress got into serious kick-ass shape for her starring role in last year’s action movie Colombiana but now she looks like she is wasting away, and her dramatic weight loss could be affecting her health, RadarOnline.com can exclusively reveal.

“She looks thin and weak, and incredibly depleted,” nutritionist Majid Ali, who has not treated the star, told RadarOnline.com in an exclusive interview.

A leading nutritionist has warned that Rosie Huntington-Whiteley has lost too much weight and believes she is now barely 100 lbs.

The 24-year-old model turned actress was pictured lounging poolside with boyfriend Jason Statham in Miami recently wearing a floral bikini that revealed her concave stomach and protruding rib bones.

PHOTOS: Rosie Huntington-Whiteley Is Looking Scary Skinny

Demi Moore was already looking startling thin before husband Ashton Kutcher's latest cheating scandal, and now the actress' weight has plunged to a frightening new low, according to an expert.

As RadarOnline.com previously reported, the 48-year-old Ghost star was a shadow of her former self when she appeared at the New York premiere of her new thriller Margin Call on Monday.

PHOTOS: Demi Moore Looks Frightening Thin On Red Carpet

"She has lost another 10 pounds in a short period of time," nutritionist Majid Ali, who as not treated the star, told RadarOnline.com in an exclusive interview.

Country singer LeAnn Rimes' stick-thin figure caused a Twitter outrage over the weekend, which was made all the worse when she defended her bony bikini body.

As RadarOnline.com reported, in response to one follower’s horrified comments – she called Rimes “scary skinny,” the newlywed tweeted: "Those are called abs not bones, love...This is my body, and I can promise you I'm a healthy girl. I'm just lean."

PHOTOS:  LeAnn Rimes Bikini Shots Set Off Twitter War

We’ve now spoken to a health expert, who wholeheartedly disagrees with LeAnn’s assessment.

"She is very underweight, those are definitely hip bones and not abs," Dr. Majid Ali (who has not treated the star) told RadarOnline.com in an exclusive interview. "She looks like she may weigh no more than 100 to 105 pounds literally - dripping wet.