Actor Bradley Cooper couldnt avoid remembering his darker days while making A STAR IS BORN.
In the Oscar remake, Cooper co-stars as Jackson Maine, a rocker battling alcoholism and drug addiction as he falls in love with his musical protege Ally (played by Lady Gaga).
The movie also marks Cooper's directorial debut.
In 2016, Cooper revealed in an interview with Barbara Walters that he struggled with drugs and alcohol.
It's that past that Cooper now says helped his work as Jackson.
"Anytime you're trying to tell the truth you need to go to places and use things that have happened to you, or you've read about or experienced," Cooper told Variety.com at the Toronto International Film Festival premiere.
"And that's all part of the beauty of turning whatever things you've gone through into a story. I find that to be very cathartic. I remember learning that in grad school, our teacher said all the insecurities, all the dark stuff you get to use that and that's really the truth," he added.
At the time of the Walters interview, Cooper said he was sober from drugs and alcohol for 11 years.