Rogen and Streisand set out on mother-son road trip

Barbara Streisand and Seth Rogen in 'The Guilt Trip'. Photo / Supplied

Barbra Streisand took some persuading to appear in her latest movie.

Another sunny afternoon in Beverly Hills and film and music icon Barbra Streisand and Canadian goofball Seth Rogen have turned a press conference promoting their new mother-son road trip movie comedy into an entertaining showcase of their age-ignorant, unlikely newfound bond.

As 30-year-old Rogen explains: "The way we talk in the movie is not a long way off how we talk in real life. It's a lot of me trying to explain things about modern times and her trying to feed me stuff I don't want to eat."

In The Guilt Trip, Rogen's character, Andy, is desperately pitching an organic cleaning product to industry bigwigs. His mum Joyce (Streisand) finds herself tagging along partly due to Andy's guilt and partly thanks to his secret attempt to reunite her with a long-lost love.

While Rogen, star of Knocked Up and 50/50, didn't hesitate to sign up to the movie, Streisand took a year of convincing, during which she went out of her way to find excuses to turn down the role.

Although she starred as Roz Focker in the Meet the Parents franchise, she hadn't taken a lead role in 16 years and admits she is dubious about where the film industry is heading.

"I remember being on a boat in France and my friend, who's an architectural critic said, 'An actor has a craft and you're an actor and you should be using your craft. Do your thing'."

At the time she was trying to get movies made as a director. "But that's very, very hard. It's not the same as when I last made a film.

"Studios are not interested in love stories any more or any movies over $15 million. It can be $100 million and that's okay. Even $200 million is okay to lose! But the movies that I'm used to making or liking are movies that cost $18 million to make. People aren't interested in those. It's a different time now. I don't like it as much."

She admits to orchestrating diva demands to keep filmmakers from chasing her for the role.

"I made it very difficult for them to hire me because I kept wanting an out," confesses the Emmy, Oscar, Grammy and Tony-award winner. "I would say, 'I would never do this film'.

"Then I said, 'I really don't want to [drive] to Paramount because it's two hours each way so would you rent a warehouse and build the sets no more than 45 minutes from my house?'

"They said yes!"

Her next requirement, quickly agreed to, was that she wouldn't be picked up for work anytime before 8.30am, having disliked the early starts required on the Focker films.

"My husband [actor James Brolin] and I stay up till 2 or 3am so we don't function well at 6am. And as Seth says it's very hard to be funny at 7.30am."

While Streisand is close with her son Jason (from her first marriage to actor Elliot Gould), Rogen admits his own relationship with his mother is reflective of Joyce and Andy's dynamic in the film.

"I have a good relationship and I see my parents a lot but it's a lot like in the movie. For no reason I get annoyed and find myself reverting back to the mentality of a 14-year-old kid who just doesn't want to be around his parents.

"It's one of the things I related to most in the script - that dynamic where your mother's trying and the more she tries the more it bugs you.

"And the more it bugs you the more you see her trying to say the thing that won't annoy you. And she just can't!"

The Guilt Trip is screening in cinemas now.