Madonna's publicist says it isn't so, but a source who knows the pop star's plastic surgeon says Madonna underwent a plastic surgery this spring.

"A mid-face lift," says the source as quoted by the media. "It's meant to make the cheekbones more prominent."

She's lost weight and may look a bit haggard, the source also suggests, giving as the reason the stress induced by constant media coverage of her alleged relationship with Yankee Alex Rodriguez.

Friends are concerned about the singer's health, a Madonna pal adds. "They're worried her upcoming tour will take an additional toll, and would like to see her gain some weight."

Dr. Tahl Humes (who does not treat Madonna) of Vitahl Medical Rejuvenation Spa in Denver says she "would recommend using dermal fillers to restore her look," if Madonna insists on the medical route to youth (not a stretch, since she’s been known to carry vitamin B-12 shots on her person).