Dan Fogelman based new film My Mother's Curse on a cross-country trip he took with his mum five years ago.
In the film, Streisand will play funnyman Seth Rogen's mother, but Fogelman reveals she's really playing his mother, who died in 2008.
He tells WENN, "It's about me locked in a car with my mother for two weeks from New Jersey to Vegas. It took a while to get Barbra but she's become my adopted mother. She's the greatest lady.
"It's really special. We literally wrapped last week in Las Vegas. I think it's gonna be really special. My mother died three years ago, which is the saddest thing ever because she was a Jewish woman from Brooklyn and Barbra Streisand was her end all, be all in life. It's a nice homage to her.
"She's playing a character, Joyce, which was my mum's name and she collects bobble head frogs like my mum did. In many ways it's based on my mum."