Angelina Jolie's disturbing behaviour on the set of new movie Salt has reportedly got her co-workers worried for her physical and mental well-being.

According to on-set sources, the actress has been an emotional wreck when she's not in front of the camera, amid persistent reports that her relationship with Brad Pitt has reached breaking point.

An insider said: “Angie’s been crying in her trailer most days and is barely eating. She keeps forgetting her lines and she’s been shaking and staring into space.

“In fact, it’s been so bad that some crew members have suspected she’s using drugs, although that’s out of the question. But the ones who know her realize it could be something much, much worse if she’s self-harming.

Ther insider adds to Britain's Now magazine: “When she’s at home she just about holds it together, but she stays up listening to the same song over and over and rarely sleeps.”