Great expectations for Diaz and Lopez's new film (+trailer)

Matthew Morrison, left, and Cameron Diaz are shown in a scene from 'What to Expect When You're Expecting.' Photo / AP

It's like Hollywood threw a baby shower - What to Expect When You're Expecting comes with a cast including Cameron Diaz, Jennifer Lopez, Glee star Matthew Morrison, Elizabeth Banks, Chris Rock and Dennis Quaid. It's an adaptation of Heidi Murkoff's best-selling, non-fiction pregnancy manual, first published in 1984; the movie version tracks five couples about to embark on parenthood, and the individual struggles they endure from conception to delivery.

It's an ensemble comedy which follows the likes of New Year's Eve, and Valentine's Day with its stars thrown into intersecting plotlines in the hope that something sticks. And though it's pretty much exactly what you'd expect, it's better than its predecessors.

Lopez plays a woman unable to conceive with her husband, played by Rodrigo Santoro and they navigate through the difficulties of the adoption process.

In real life, Lopez, 42, recently divorced from Marc Anthony, is the mother of 4-year-old twins. Unlike her character, she is familiar with the subject of pregnancy and parenthood.

"I found reading What to Expect to be so incredibly accurate," she says. "It's the first thing you buy when you find out you're pregnant because it takes you through all the stages. It helps you not to freak out about how your body's changing."

The Cameron Diaz and Matthew Morrison storyline deals with an unexpected pregnancy in a new relationship. Diaz plays an overzealous TV fitness guru and Morrison a Dancing with the Stars pro dancer.

The highlight for Diaz, who has never experienced pregnancy, was the joy of some artificial side-effects.

"The pregnant breasts were amazing. As soon as I had them on, I thought, 'These are awesome'," she laughs. "I flashed the other actors."

With such a female-dominated subject matter, the comic relief comes in the form of "The Dude Group", a support unit of fathers led by Rock who tote their babies around a park swapping fatherhood tips.

Says Lopez: "The dad's group, I thought, was pretty genius. Dads who are really involved with their babies, good dads who need other dads to kind of help them through fatherhood. We forget that they have their own set of challenges. I thought that that was a great addition to this type of movie."

Elizabeth Banks was probably the only relatable woman in terms of the semi-realistic, albeit exaggerated, bodily functions pregnant women undergo.

"Pregnancy can be really uncomfortable for a lot of women," she says.

"But I didn't carry my own baby so my real life experience was nothing like mine in the movie or anyone else's in the movie," she says.

Banks and her husband, sportswriter Max Handelman, are parents to a baby boy via surrogate, March 2011.

She says, "Not being able to get pregnant was an issue that weighed on me and on my husband for many years, and now that we have a son, it's an extraordinary experience to hold this little dude in my arms."

Despite the various comedic elements the subject matter provides, naturally, the film is emotionally charged at times, particularly surrounding the adoptive parents.

Says Lopez: "It's funny but before the movie, I never thought about adoption at all. I just always wanted to have my own baby and that's all I was focused on. But during the making of the film, when I held those two little Ethiopian twins, I fell in love instantly. It occurred to me how easy it is to embrace a child who has nothing. It's a really beautiful, selfless act of love," she says.

As for her birthing experience, she says, "Women will hate me for saying this but I had an incredibly easy pregnancy. I'm sorry, don't hate me," she laughs. "I was on tour until I was six-and-a-half months pregnant, dancing every night on stage, and I didn't really blow up until I was eight months pregnant. I didn't have the normal symptoms; no throwing up, I wasn't extra tired, and I didn't get haemorrhoids.

"What's funny is that the minute that I had the twins, I said to Marc and the doctor, 'How long do I have to wait until I can get pregnant again?"'

Given that her experience was so effortless, and now that she's in a relationship with her much younger beau, Casper Smart, 25, a backup dancer and choreographer, perhaps there is a possibility of expanding her brood.

"I don't know. We have to see," she laughs. "We only have so many years that you can do that."

Heidi Murkoff, author of the self-help book which sold more than 35 million copies, says, "When I wrote What to Expect, it was inspired by my first pregnancy. Sitting here now, I was definitely not expecting this," she says, gesturing to Jennifer Lopez and Cameron Diaz, seated next to her.

"Let's just say that. It's been an adventure. It's been unexpected."

Lowdown

What: What To Expect When You Are Expecting
Who: Stars Cameron Diaz, Jennifer Lopez, Matthew Morrison, Chris Rock, Elizabeth Banks and Dennis Quaid
When: Opens Thursday

-TimeOut