Top docs and diet guru weigh in on singer FAITH HILL’s shocking  new gaunt look.

Faith Hill has long been known for her strict workout regimen and diet dedication but at the Grammys the 45-year-old’s recent dramatic weight loss appears to have taken a toll.

“Her neck is extremely gaunt and her clavicles, they are ripping that bodice,” Dr. Fred Pescatore, author of The Hamptons Diet, who has not treated the star, told

“It is certainly very aging on her and is an unhealthy weight,” the nutrion expert said, adding that fat injections in her face wouldgive Faith a more youthful and healthy look again.

Meanwhile, nutritional expert Dr. Majid Ali estimates 5’9″ Hill’s weight at as low as 115 pounds, and warns: “Her color and general look is good, but she should not go lower.”

Hill’s wardrobe on the biggest night in music was far from flattering on her new thin frame, which is a far cry from the sexy voluptuous curves she boasted in 2010.

“Little black dresses have a way of further slimming a person who is already tall and very slender,” NutriFit CEO Jackie Keller says.

“The dress she’s wearing may be purposely looser than it needs be, as is often done when someone is trying to look more full-figured, rather than thinner.”