A recent rainy afternoon at the Four Seasons Hotel in Beverly Hills found Ms. Streisand, 70, impeccably dressed in a black suit and crisp white blouse, and Mr. Rogen, in baggy jeans and a T-shirt noticeably fraying at the collar, exhibiting that same odd-couple chemistry. Together they joked about everything from Mr. Rogen’s performance (“It was about the general modulation of annoyance”) to Ms. Streisand’s reputation as a perfectionist. These are excerpts from their conversation.  Q. “The Guilt Trip” is about a maternally invasive widow and her dryly condescending son who drive together from New York to San Francisco. How would you describe the movie?  BARBRA STREISAND I like to refer to this as “a different kind of love story.” It’s not ha-ha funny. There’s no sight gags or anything. It’s about a mother and son getting to know one another.  SETH ROGEN There’s no making out in the movie.  ROGEN Exactly. We leave it out so there’s somewhere to go.  Q. Seth, were you familiar with Barbra’s movies?  ROGEN Not every single one. We both plowed through each other’s catalogs. You have to in case it comes up conversationally.  STREISAND You don’t want to look like a fool. I haven’t seen “Superbad.”  ROGEN It’s pretty funny. It’s dirty.  STREISAND It’s dirty? I’m kind of a prude.  ROGEN Um, not really. I saw “Bad Teacher” with you, and you enjoyed it. And that was pretty dirty.  STREISAND I don’t like certain language.  ROGEN [Laughs.] What’s funny is that you say that, but you spent all day in a car with me, and I did not censor myself a great deal.  STREISAND In life I’m not a prude. In film I’m still a prude. Like when I saw that movie, “Hangover,” with the guy, Javalopolis?  STREISAND He was naked in the elevator, and I heard later it was not his real thing. But everybody thinks it’s his real thing.  ROGEN So what’s the difference? [Laughs.]  STREISAND Well, that’s the advice I’m going to give you: Don’t stoop so low.  ROGEN I’m just as sexually uncomfortable as the next guy.  STREISAND People are going to have to pay big money to see any part of me naked.  ROGEN Exactly. We’re still negotiating!  Q. Barbra, Anne Fletcher first approached you to do this film in November 2009. A year later you finally agreed. Why the heel dragging?  STREISAND I didn’t want to just play another Jewish mother [after “Meet the Fockers” and “Little Fockers”]. With this the fact that I had a son made a big difference. I could relate this to my son and the times we went through, those rebellious periods, how you’re walking on eggshells, how you don’t want to say the wrong thing, but you’re always saying the wrong thing.  Q. What did your son, Jason, think of “The Guilt Trip”?  STREISAND He liked it. I read it out loud with him in bed. [Pauses.] Don’t take this wrong. He was recovering from back surgery  Q. Your film backgrounds are very different — musicals and heartfelt dramas versus improvised raunchy comedies. What did you learn from each other?  ROGEN I think what was surprising was that we actually had a very similar working style.  ROGEN We both understand where the cameras are and how editing works, and I think that makes improvising a lot easier. We’ve both been on the other side of the camera in various ways, and I think that makes you a totally different actor. Once you’ve produced a movie, directed a movie, it makes you understand that a lot of things that actors do are obnoxious.  Q. Barbra, have you done many improv-heavy films?  STREISAND I did with Dustin [Hoffman] on “The Fockers.” We were in the same acting school when I was 16, 17 years old. I used to baby-sit to get free acting lessons, and he was the janitor. So Dustin and I, we could do that. Not many people can do that, I find.  ROGEN Sometimes I’m improvising and I’m looking at the person, and if there was a caption beneath them it would be, “What is this person doing right now?”  Q. Do you think that some of your professional similarities stem from the fact that you both started working at a young age? Seth, you were doing stand-up at 13, right?  STREISAND When I did summer stock, I’d just turned 15.  ROGEN I think one of the biggest things we have in common is that we both take our work very seriously — and we both want to go home. A lot of people are more than happy to keep working and shooting, and you get no sense that they like it at home. I love working, and I want it to be as good as it can possibly be. But then I want to go home and spend time with my dog and my wife and watch television.  Q. Seth, you’ve said in the past that you find it nerve-racking to work with actors who aren’t part of your insulated group of friends.  ROGEN It’s always conceptually easier to work with people you’re familiar with. But it doesn’t make a difference at all. We got along really great.  STREISAND Right from the top? Or were you a little scared before you met me?  ROGEN I didn’t preconceive. I’ve worked with a lot of people who people have told me are superdifficult, and I haven’t found them to be difficult at all. I’ve also worked with people that people have said are easy, and I’ve hated them. I’ve worked with dudes in their 20s who were way more difficult than Barbra to work with. [Looks at Ms. Streisand.] You don’t rank anywhere near the top area of difficult. It was really easy.  Q. Food scenes are famously tough on actors. Barbra, did you ever think that after such a long break your return to film would include a bit where you’d power-eat a 50-ounce steak?  STREISAND That’s where the filmmaker in me came out. The actress did not want to do that scene. I said, “Can you come up with something other than eating?” But I thought it would serve the film so I said: “O.K. I’ll do it.” But it was hard. I don’t eat steak. One bite for me is enough. So they had to devise a way to make things look like steak. I still had to eat it for three days.  ROGEN It was so gross.  Q. Was the experience of “The Guilt Trip” enough to convince you to not put so much time between film roles?  STREISAND I actually did enjoy this — as opposed to some of the “Focker” movies. I had fun in the first one. The second one?  ROGEN I’m surprised you watched it, honestly. [Laughs.]  STREISAND I never saw the complete movie. I was in Europe spa-ing, going from spa to spa. And they were sending me bits to O.K. So I would download them and watch the bits on my computer. It’s the first time in my life I never saw the whole movie.  ROGEN You’re not alone. [Laughs hard.]  STREISAND I think it did $300 million. So what do I know?
Barbra Streisand and Seth Rogen talk about their mother-son road comedy, âThe Guilt Trip,â eating steak for three days and working nude.