Brad Pitt and Angelina Jolie's relationship is to be the subject of a new documentary by Ian Halperin.
The 52-year-old filmmaker has promised to expose the intimate details behind their break-up and has claimed the Hollywood duo were estranged for more than a year before their split in September 2016.
A source said: "This is the definitive film about Brangelina and a lot of secrets are going to come out.
"Ian has covered every cough and spit of their relationship and will reveal the real reasons behind Angelina filing for divorce.
"The biggest shock will be his claim that the couple were apart for more than a year prior to their break-up."
Brad, 53, and Angelina, 41, are currently in the midst of a high-profile divorce and the documentary has been described as "the last thing they need".
The source told The Sun newspaper: "[Ian] and his team have also managed to acquire some never-before-seen footage and interviews with both Brad and Angelina.
"Lately the pair have been trying to put on a united front and keep their divorce discussions quiet.
"This is the last thing they need."
Meanwhile, Brad is reportedly "much happier" because he has been "spending more time" with his children in recent weeks.
The 'Fury' star is feeling more upbeat since he has started seeing his kids – Maddox, 15, Pax, 13, Zahara, 12, Shiloh, 10, and eight-year-old twins Knox and Vivienne – more often.
A source said: "He seems to have a more positive outlook. Things seem much better now ... He can spend more time with them ...
"He seems much happier. He has missed his kids terribly. The kids are his whole world. It's all he cares about."
And the Hollywood star is happy to work with his estranged wife in the hope it will make the split easier on their children.
The insider said: "Brad is willing to work with Angie so they can have peace for the kids. What it ultimately comes down to is that he just wants to be with the kids."