The unidentified source said the "Tomb Raider" star has been diagnosed with the form of diabetes which typically develops during the second half of pregnancy, The Daily Mail said Saturday.

"Angie has gestational diabetes. She found out about a month ago and has been trying to keep it under wraps," the source said. "She's been seeing a nutritionist about it frequently."

Gestational diabetes, which reportedly occurs in an estimated 2 percent of pregnant women, can cause problems for both the mother and her unborn child if not properly treated.

The Daily Mail said diet and exercise are common ways to treat the condition, which also causes sufferers to be more susceptible to developing type 2 diabetes.

Jolie, currently in Texas with husband Brad Pitt and her four other children, is reportedly carrying boy and girl twins.