The writer and director of This Is 40 isn’t the same one who wrote and directed The 40-Year-Old Virgin. Judd Apatow has come a long way since making comedies about horny single men, but he hasn’t lost his touch – he’s still a very funny guy. In his most personal movie yet, Apatow revisits Debbie and Pete, the married couple from his 2007 movie Knocked Up, which was played by Leslie Mann and Paul Rudd. Recently, we got the chance to talk to Judd Apatow about all sort of things, including the working relationship between him and his wife, the cursing scenes with his kids and what it was like to guest edit the very first comedy edition of Vanity Fair.

What was the toughest thing about turning forty, and how did you overcome it?

Judd Apatow: I overcame it by making two movies with the number forty in the title. I claim that I haven’t had a nervous breakdown from turning forty and that it was more thirty, but the evidence of the two movies seems to prove I’m full of it.

This was a very funny movie. I don’t know if you’ve seen the movie Hitchcock and the whole husband and wife relationship there…

It’s very similar. I did watch it with Iris [Apatow] the other night. Iris is ten. We had to cover her eyes during the Ed Gein sequences. Was that a bad piece of parenting? Leslie wasn’t home. I tried to show her Psycho. I was like: “I don’t want you to see the bad part, I just want you to get the feel for it.” I cover her eyes and she screams: “What are you doing?!”

Judd, how much did you know about a woman’s perspective of turning forty? Did you and Leslie bounce ideas off one another?

We talked about the movie for years together and that’s where the ideas come from and it’s a little bit of a coded conversation where we are really debating our own problems with each other, so Leslie can complain about Pete but not about me.  So I’ll say, “Don’t you think we should have a scene where we point out how really controlling Debbie is?” And she’ll say, “Yeah, but maybe we should include a bit where Pete admits he’s a dick.” And then we go back and forth like that, kind of subtlety talking to each other for a long time. And at the end, it mutates into this other weird thing which is a combo of me and Paul’s worst traits into one monster husband that Debbie has to deal with.

The Lost references are great. Is there some inside joke rivalry between you and J.J. Abrams?

No, our daughter watched Lost in about six weeks and was crying a lot. We thought, “Are we bad parents for allowing this?” But then we’re too lazy to keep up with her to know what the next episode is, like if it’s inappropriate, so we just kind of let it happen and then we realized there was some bad parenting happening. It was out of control and I thought, “I really don’t know what to do here but it does make for a good couple of jokes in the movie.” That’s what I usually do when I should make a strong parenting decision. I kind of let it play out to see if a joke results from it. It’s probably not a good idea. But then JJ read the script and came to previews, and I made sure that he was happy. But he is a geek who has ruined our lives.

Was there a lot of improvisation in the scenes between Albert Brooks and John Lithgow?

I watched the dailies recently and the best line that Albert came up with, on the fly – which is the fun part of loosening it up at the end after getting it scripted and then starting to play. Well, we knew that we wanted Albert’s character to be excited about how much money John’s character makes. So I was watching the dailies and it’s my favorite wording of the joke in the movie. Albert tells John: “Every time I don’t see a hunchback, you make money.” (Lithgow plays an orthopedic surgeon in the film.) Albert made up that one. He would actually email me jokes the night before, which would be at the top of any of my jokes. I was very happy about that.

How do you handle the cursing scenes with your kids. Did you explain the difference that it’s okay to curse if you’re in character?

Well they use the cursing against me now. They tell me, “Well everybody curses in Superbad.” [Maude Apatow] is finally using it as revenge against me. I knew it would happen one day. “You make your whole living off of cursing. How can you not like cursing?”

Is there anything Leslie Mann wouldn’t do that you’ve asked her to?

The ones you think I made her do, she thought of usually. We did try and get across the mystery disappearing in a relationship and people being totally open in a way that after many years, it becomes disgusting and not sexy. We were trying to think of two examples, one was “will you look at this” (between my butt cheeks) and the other one was being on an iPad in the bathroom.

What was it like guest editing the first comedy edition of Vanity Fair?

I took the movie around New York to try to get people interested in writing about it. And I knew that a friend of mine had done something like that with another magazine, so I just tossed out the idea thinking they wouldn’t let me do it. And then they really let me do it and it was a crazy amount of work for about half a year. It was one of those things were I could have done very little, and they wouldn’t have cared. But I got really into it and drove everyone crazy.

It was fun. It was great to talk to Albert for that Q&A. I got them to do an interview with Nichols and May, which they hadn’t done an interview in 50 years, and then they did. It was exciting. And I got to take a picture with Steve Martin, which was a career highlight. And Mark Sullivan, the photographer, is brilliant. If I came up with a funny idea for photo, then he realized it and it was pretty remarkable. People seem to like it too. The Freaks and Geeks article got the most page views in the history of Vanity Fair‘s website.

This Is 40 hits in theaters on Friday, December 21st.