Angelina Jolie has always been thin — but not THIS thin! You can clearly see bones jutting out on the actress and mom of six  — and her tiny calves don’t even fill her boots!

Celebrity weight expert, John Spencer Ellis, from The Real Housewives of Orange County, tells HollywoodLife.com that Angelina Jolie, at 5’8,” looks like she only weighs “between 100-105 lbs.”

“With her height and slim frame,” says John, Angelina should weight more like “125-135 lbs … which is still on the thin side.” Angelina is “not the optimal weight for someone in her height bracket. She could stand to gain at least 5 lbs of fat and 5 lbs of muscle.”

With Angelina’s packed schedule and busy life, her weight loss may be induced by stress.  “In her case, stress could have increased her metabolic activity, causing her to burn through the few calories she does eat,” John explains. “Also, I think her fear of being heavy is a big part of it. There is a lot of Hollywood pressure to be really thin.

Whatever the reason, Angelina’s weight looks to be bordering on unhealthy. “She is borderline emaciated” John says. “It doesn’t appear that she does any strength training, because you can see there is no structure or integrity to her upper body– no muscle tone in the arms at all. It looks like she’s not eating much at all”  — John estimates she eats less than 1200 calories per day — “and doing cardio.”

If it’s not stress or pressure, then John has one other theory. “Part of her weight loss may be a sub-conscious attempt to ‘look and feel’ like part of the people she helps in Africa.”

—Allison McNamara