Though Fox wasn't pregnant while shooting the comedy (also starring Paul Rudd, Melissa McCarthy and Jason Segel), she did pick up a few parenting tips from the film's star, Leslie Mann, and her husband, writer/director/producer Judd Apatow.
"Their kids are so well adjusted," Fox said of the couple's daughters, Maude, 13, and Iris, 8. "They're the best kids and they both have really awesome personalities -- especially Iris. She's just a hysterical little ball buster. I think she's super funny, and then Maude is a genius! They are just good kids, which I think is rare for kids that were raised in this industry, so they did a good job."
During the press junket, Fox also opened up about her audition process for the movie, in theaters Dec. 21. After running lines with Apatow, 45, Mann, 40, and Rudd, 43, Fox recalled, "Judd was like, 'Paul, can you come into the store and you guys have an awkward conversation? Then we had to do all of this improv, which I am not familiar with at all, so I was scared sh-tless."