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Barbra Streisand and Seth Rogen play mother and son in their new film The Guilt Trip, and as The Insider's Debbie Matenopoulos found out, the duo's real-life relationship is very much like their on-screen personas.

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"I love to touch my son's hair," Barbra says about adopting certain aspects of her real-life relationship with her son Jason Gould to Seth. "And he always goes like this [moves away] -- at this point, he gave up," she jokes, touching Seth's curls.

"I just let her do it ... I'm resigned at this point," Seth says.

Video: Seth & Babs Set Out on 'The Guilt Trip'

And it turns out, Seth is also the one who played Duck Sauce's huge club hit Barbra Streisand -- which Glee covered in season two -- for her first. It turns out, she had previously never actually heard the song named after her.

"We played you that song for the first time on set, I remember," Seth tells Barbra during their sit-down. "You had heard of it, but you hadn't heard it."

"See -- I rely on him for all this contemporary music stuff. No kidding ... I must have been aghast," she says, trying to remember.

"You liked it," Seth laughs.

Video: Streisand Reveals Doubts Returning to a Lead Role

"What I love about it is that they say my name right. Isn't that wonderful?," Barbra elaborates. "It's Barbra Strei-sand -- it's sand on the beach. And even my, you know, my brother calls me Barbra Strei-zand with a 'z.' I said, 'Shelley, it's spelled with an s!,'" she laughs. "Maybe he'll get it one of these days."

Check out the video to hear how Seth feels about the legendary singer playing his mother, and if a duet is in the future for the pair. The Guilt Trip, about a mother and son taking an unexpected road trip together, hits theaters today.