Window Polished Fire Agate: Doctors Explain: What's Wrong With Angelina's Face

Angelina Jolie was photographed in Venice, Italy Wednesday afternoon with two protruding muscles where her chin meets her neck.

The photo was not altered, as Jolie, 34, sported the same facial protrusion at the BAFTA awards in February 2009 (see bottom photo, at left).

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consulted a number of plastic surgeons to find out what's really going on because, as Beverly Hills-based Dr. Gabriel Chiu tells Us, "it's unlikely that the banding can occur from strong facial muscles alone."

Dr. Elie Levine, who has not treated Jolie, says that it appears she's "received Botox to her face and likely her neck" because she shows "no wrinkles along the sides of her eyes (the crow's feet) despite that very large smile... and her forehead is smooth."

See what Jolie used to look like in her old modeling shots

Botox paralyzes muscles, causing one to "recruit other muscles that are not regularly used to twisting the neck and smiling widely" to compensate, he adds.

Dr. Chiu believes Jolie may have had a "minimally invasive procedure" to lift and suspend "the tissues in her neck, jaw line and lower face."

Dr. Brian Glatt concurs. "Angelina appears to have had a procedure done to tighten her lower face, neck, and jaw line such as a mini or lower facelift," he says.