The 'Fury' star was reportedly "caught off guard" when his estranged wife Angelina Jolie decided to file papers to the court late on Monday (19.09.16).
A source said: "He is beside himself and has been crying. He was completely caught off guard and blindsided and had no idea she would do this.
"Angelina filed the court papers a minute before the courts closed on Monday night. He didn't have a lawyer or anything. She had threatened divorce in the past but he did not think she would file this time. He is completely devastated and beside himself. He is a shattered man."
Whilst another insider added to Us Weekly magazine: "He's extremely upset. But he is totally focused on just being helpful and making sure his kids are doing as well as possible."
The 52-year-old actor - who is reportedly being investigated by the FBI over claims he verbally and physically abused one of his children on a private plane last week - was really "committed" to making his marriage work.
A source said: "Brad did not want the marriage to end. He was committed to doing what he needed to make it work. He was open to therapy."
Whilst a pal added: "He is emotionally torn. Right now, he is devastated. He still loved Angelina and would have preferred they fight to make the marriage work. He was willing to do whatever it took to save the marriage and didn't know Angelina had already given up on it. He has wanted to protect the children. He didn't want it to play out publicly."