Jennifer Aniston reportedly collapsed on the set of her new movie.

The Daily Mail reports that the actress was filming "The Break Up" with her co-star and rumored beau Vince Vaughn when she collapsed after complaining of nausea and severe headache. She was officially diagnosed with heatstroke.

But sources on the set say she passed out due to stress.

An insider said: "She's been walking around with a sad look on her face and has not been her usual self. She couldn't have escaped all the stories about Brad and Angelina, and it looks like the situation has taken its toll on her."

Brad Pitt and Angelina Jolie have repeatedly denied rumours that they are a couple since Pitt and Aston ended their marriage in January.