Angelina Jolie thought working with Brad Pitt on 'By The Sea' would help them communicate better as a couple.
The actress - who separated from her estranged husband in September 2016 - directed the marital drama movie two years ago and admitted she thought it could have had a positive impact on their relationship by working together on a big project.
Speaking to The Hollywood Reporter's podcast 'Awards Chatter', she said: "We had met working together and we worked together well...I wanted us to do some serious work together...I thought it would be a good way for us to communicate.
"In some ways it was, and in some ways we learned some things. But there was a heaviness probably during that situation that carried on and it wasn't because of the film.
"It was something that we were dealing... things happen for different reasons, and things... why did I write that exact piece? Why did we feel that way when we made it? I'm not sure."
The couple - who together have six children - met while filming 'Mr. & Mrs. Smith' in 2005, and Jolie candidly explained how she had a difficult time in the decade after they sparked a romance.
She added: "Over the span of that decade, I did lose my mother. I did have my mastectomy, and I did then have an ovarian cancer scare and have that surgery as well, and other things of course that happened in life that you go through.
"A piece of art can be something that's healing or something that's difficult. I don't know. I'm glad we did that film because we did explore something together. Whatever it was maybe it didn't solve certain things, but we did communicate something that needed to be communicated to each other."
Together, the former couple have Maddox, 16, Pax, 13, Zahara, 12, Shiloh, 11, and nine-year-old twins Knox and Vivienne.