With news breaking of Brad Pitt and Angelina Jolie's divorce, reputable US media outlets are now reporting that an on-set affair was the catalyst for the high-profile couple's split. 

Page Six is currently claiming that the Oscar-winning actress felt compelled to dump her partner of 12-years when she learned he was cheating on her with a co-star.

Angelina, 41, and Brad, 53, famously met on the set of Mr. & Mrs. Smith when the latter was still married to Jennifer Aniston. 

Page Six adds that a private investigator hired to monitor Mr Pitt while he filmed his latest movie in London confirmed Ms Jolie's worst fears

"She hired a private eye because she felt that he was fooling around with her on the set, and it turns out, he was. And that was the final straw," a source has told the media outlet.

The Inglourious Basterds star has been rumoured for months to have grown increasingly close to his Allied co-star, Marion Cotillard.

Mail Online furthermore reports that Angie had grown weary of her spouse's lifestyle and approach to parenting.

She is seeking full physical custody of their six kids, but is willing to grant him legal and visitation rights.