Over the moon about starting a family, TV fitness guru Jules (Cameron Diaz) and dance show star Evan (Matthew Morrison) find that their high-octane celebrity lives don’t stand a chance against the surprise demands of pregnancy. Baby-crazy author and advocate Wendy (Elizabeth Banks) gets a taste of her own militant mommy advice when pregnancy hormones ravage her body; while Wendy’s husband, Gary (Ben Falcone), struggles not to be outdone by his competitive alpha-Dad, who’s expecting twins with his much younger trophy wife, Skyler (Brooklyn Decker). Photographer Holly (Jennifer Lopez) is prepared to travel the globe to adopt a child, but her husband Alex (Rodrigo Santoro) isn’t so sure, and tries to quiet his panic by attending a “dudes” support group, where new fathers get to tell it like it really is. And rival food truck chefs Rosie (Anna Kendrick) and Marco’s (Chace Crawford) surprise hook-up results in an unexpected quandary: what to do when your first child comes before your first date?

Inspired by the perennial New York Times bestseller of the same name, ‘What to Expect When You’re Expecting’ stars Chris Rock, Rob Heubel, Anna Kendrick, Cameron Diaz, Dennis Quaid, Jennifer Lopez, Rodrigo Santoro, Joe Manganiello, Chace Crawford, Matthew Morrison, Brooklyn Decker, Thomas Lennon, Rebel Wilson, and Wendy McLendon-Covey. The film opens in cinemas May 12th in the US and May 25th in the UK.

The film takes a slightly approach to the ‘What to Expect When You’re Expecting’ book right?

Jennifer Lopez: Yeah. The movie and the book are very different. In the book it tells you exactly what’s happening, and it’s everybody’s common experience. For example, “The third month, this is what happens, this is how big the baby is, this is how you’re feeling, this is what your bodies doing. At this time, it’s this big, you should be this big now,” all these kind of things. And for everybody, if you ’re having a normal pregnancy, this is how it should be. In the movie it’s really about the opposite, it’s about how everybody is going through all of that, but everybody’s experience is completely different – and how funny that can be (laughs).

Having read the book when you were pregnant, how did that help prepare you during that whole process? I can imagine it being a great tool, and at times, during the more stressful periods, a bit of a friend.

Jennifer Lopez: Oh yeah (laughs). I found the book to be so incredibly accurate while I was pregnant, it was crazy – honestly! I just saw why the book is so popular and why, for so many people, it’s the first thing you get once you find out you’re pregnant. It takes you through everything. And when you get pregnant, it’s this thing that everybody’s talked about your whole life, but you know nothing about it when it’s happening to you. This book helps you not freak out (laughs). It really helps you to calm down as an expected mum, you know?

Also, I remember sitting in my bed with my twins, I had a C-section so I was obviously in a lot of pain. And I get like this sometimes, I was like, “No painkillers,” because I don’t drink, I don’t smoke. I’m like, “I’m not gonna take the painkillers!” I’m crazy (laughs). So I’m going crazy from the pain, and I want to hold the babies but I can’t because it hurts so much. So I have this baby nurse helping out, at the time I was thinking, “The babies don’t love me, they’re not gonna know me, they’re gonna love the nurse,” (laughs). And I opened the book, and its this specific day, generally, where you get this hormonal drop, on the tenth day, it’s called “the baby blues.” I was so happy I found that, I was like, “That’s what is happening to me, the babies will love me!” (Laughs) It made it so much better because you do really feel out of sorts and you don’t know what’s going on at times. In that sense it’s such a great tool, book, everything….friend in that moment!

Holly has to nudge Alex slightly into fatherhood, into adopting. “Dude Group” is a big help?

Jennifer Lopez: Holly is so into the adoption and so into having a baby, and Alex, my husband, he’s not as ready as she is. He’s comfortable with the idea, he wants to have children with her, he wants to have a family with her, but at the time the adopting thing is probably a lot for him to handle. Because Alex is having so much trouble, Holly’s friend says, “Why don’t you send him to this group that my husband goes to. He was totally terrified of becoming a dad, and once he started hanging out with other dads he saw that it was kinda OK. Now he’s a great dad.” So she convinces her to send him to “Dudes Group“, and these guys help him get used to the idea that it’s happening and what it is and what he can expect as a father. “Dudes Group”, they’re like this diverse group of funny dads (laughs).

How was it working with Rodrigo Santoro as Alex? 

Jennifer Lopez: He’s amazing, he’s a really great actor. It’s so funny, the minute we came together it was like we were a couple (laughs). I don’t know if it’s because we both have Latin backgrounds or something, we just immediately found the characters through each other. It was like a, “Because you know who you are, I know who I am,” type of thing. We clicked instantly. It was a really fun experience working with him. Us as a couple in the film, we’re the couple that people want to hang out with because they get along, they really love each other – that was nice to play. I think with them, they’re so into doing their thing, they left it a bit too long, so they have to catch up. Rodrigo was a lot of fun.