Speaking to Parade's Jeanne Wolf about her new movie "Life As We Know It", Katherine chatted about her battle to quit smoking, movie motherhood and how husband Josh Kelley copes with on-screen romance.

Movie mothering versus the real thing

"I thought I was going to be getting some advance training in how to be a real mother while I played the role in the movie. But the adoption of my baby from Korea went on ahead of schedule, and my daughter, Naleigh, arrived weeks before we began filming. I was really thrown into hot water pretty quickly. I was sort of faking changing diapers on the set, but at home I was doing it for real."

Sometimes you have to go with the flow.

"Even if you plan a marriage and a family, you are never quite prepared for the reality versus how you imagined it. In a lot of ways it's better, and in a lot of ways it's worse. That's life, right? It's the same with my career. It took a sudden, very sharp upward turn, very quickly, and it changed the whole course of my life. I mean nothing is the same, nothing. It was literally, like, six years ago, I was still auditioning, I was struggling, I was trying to get jobs, I was taking whatever parts I could get to pay my bills."

Helping her husband cope with lip-lock scenes.

"Actually, he and Josh Duhamel are good friends, but he would never come to the set when Josh and I had to like kiss or make out. It does make him uncomfortable because he's not an actor, he's a musician. He always says to me, 'How would you feel if I had to make out with some girl in a video?' And I'm like, 'If you have to do it, you have to do it. But I wouldn't want you to come home and tell me what a great kisser she is and I should try her technique.'"

The price of sudden success.

"Every freaking movie that I have coming out, they still are like, 'This is the one that is going to prove whether or not she's got box-office power.' I'm like, 'Please don't do that.' You are going to have some that don't do well. That's just life. I can't control it."

Smoking used to ease the stress, but not anymore.

"Now I use an electronic cigarette. I know it's ridiculous, but it's helping me not to actually smoke real cigarettes. You feel like you are smoking, and you get to exhale but it's just water vapor and not nicotine. I've been doing it for six months. Smoking sucks! The one thing I would say to my kid is, 'It's not just that it's bad for you. Do you want to spend the rest of your life fighting a stupid addiction to a stupid thing that doesn't even really give you a good buzz?'"

Still worrying about that character she left behind on Grey's Anatomy.

"I really do think about her, I really do. I'll always love that character and I will always, in my mind, protect her. I think she was a fierce, fierce woman. She went through a ton of stuff in her life, and she was a survivor, so I think she survives. I don't know if she stays a doctor or not."

Katherine explained to Canada's Metro News how her performance in "Life As We Know It" was a reflection of her own life at the time the movie was made, as the adoption of her daughter Naleigh took place just 4 days before production began:

"I related to the movie because in my own life I was getting ready to become a mom and wanting to start a family, but I didn’t expect to be doing both at the same time, so it was interesting and overwhelming for sure. I couldn’t show up to set with the same kind of focus I had in the past on other projects because I was really distracted," Heigl said.

"So what you see in my performance is pretty much who I was at that time and all I had. I gave it all I got, but there wasn’t a lot of craft involved at that point. It was just instinct. It was a fascinating psych experiment."

In an interview with Josh Duhamel in USA Today, Katherine told reporter Andrea Mandell that her friend and co-star would make a great father:

Katherine Heigl & Josh Duhamel Star In Life As We Know It Katherine Heigl & Josh Duhamel Star In Life As We Know It

"There's a couple different types of actors in this town," Heigl says. "You've got the guys who want to remain perpetual bachelors and live it up and have a great time, and you've got the guys who have the relationship but don't necessarily want to burden the good time with a family. I think Josh, from the time he was 15 on, knew he wanted to get married and have children. He's that guy. I think he really believes in family."

If you couldn't find Duhamel on the "Life As We Know It" set, he was probably hanging out in the nursery trailer "partying with the babies," director Greg Berlanti says. "He had all sorts of fun games he would play with them and learned all the ways to calm them down."

"I was a little more distracted," says Heigl, who had just adopted daughter Naleigh with husband Josh Kelley and arrived in Atlanta shortly before shooting began. "It was fun to even see him with my daughter. He's so drawn to children. He gives off some scent or something -  they gravitate toward him."

Director Greg Berlanti was interviewed by the Los Angeles Times about his work and was quizzed about the new romantic comedy. He explained how his experience working in television had helped with a tight production schedule and that it was important the movie felt as real as possible. These sentiments were echoed by Katherine who also served as a producer on "Life As We Know It":

Berlanti said his television training prepared him well. It helped him work quickly on the film, which had to be shot in less than 50 days to accommodate Heigl's schedule, and it taught him how to keep emotional material from becoming overly sentimental.

"What we were most nervous about was shying away from the tragedy too much and making it more of a broad comedy or a shticky baby boomer-type comedy," said Heigl, who produced the film and was instrumental in hiring Berlanti. "We both agreed that that wasn't the direction we wanted it to go."

Heigl said she relied on her experiences as an adoptive mother to a baby girl to help ground her character, and Berlanti said he tried to use small, intimate moments to make the movie feel as real as possible. Mostly, he relied on his instincts.

"You have to always be in tune with that voice inside you, how you react to something and trust that," Berlanti said. "With this kind of film, you have to lead with your heart."

E!'s Ben Lyons also caught up with Katherine and co-star Josh Duhamel at the promotional press junket for the movie:

Moviefone spoke via telephone with Katherine to get her thoughts on what it was like playing a new mother so soon after she became one in real life; who she'd want to raise her daughter if the unthinkable happened; and unnerving television shows that kids love and adults love to hate.

Tell us a little bit about your character, Holly Berenson. How much of you is in her?

A lot, actually. Not out of any real conscious choice. My daughter had come to me four days before filming started and it was unexpected that she came so soon. I had to dive into new motherhood and work at the same time, and just didn't have the wherewithal to put a lot of craft into my performance. So, I was just living on camera what I was living at home every day.

So, you were learning to be a mom in real life during filming. Did you take anything away from the role that you could apply to motherhood?

Mostly I think I learned not to beat myself up too much for feeling so overwhelmed initially, and nervous, and thinking that if I could control all the details, I could somehow control the situation better. It doesn't matter how well your diaper bag is packed, you're inevitably going to forget something and you need to learn to just roll with the punches a little bit. Everybody has their own style of parenting and I just had to figure out my style and embrace it. You absolutely are going to take advice from friends with children and your own parents, but it ultimately comes down to what works best for you.

I think that's what Holly and Messer learn. They start out trying to follow the rules of their neighbors, and then they just realize they need to find their own way. The best thing about being a new parent is having a good partner. I can't even imagine having to do it on your own, and I know a lot of people do.

The film portrays various families each with their own dysfunctions, but they all work. Do you think there's a perfect formula for family?

I don't. Absolutely do not. I'm a big proponent of adoption. My sister is Korean. When my parents made that decision back in the '70s, people thought it was really unusual because my mother and father already had two biological children. People thought, 'adoption is what people do when they can't physically have a child!' People didn't really understand that that's not the only reason you adopt - though it's certainly one of them. So, I've never looked at family according to society's ideas.

It sounds like your own experiences with adoption propelled your interest in the film.

Oh, yeah - for sure. I've always related to the idea of loving a child you didn't necessarily birth. My mother always used to say that, too. It never mattered how they came to her. As soon as they put that child in your arms you love them, unconditionally. I wanted to be a part of this movie because I love that universal theme.

The movie is based on this tough scenario most parents probably don't want to talk or even think about. Have you had this conversation with your husband because of this movie?

Yeah, you know, it's funny because during the adoption process it's actually a question you have to answer. They ask you to fill out a form with all the information about who you would choose to raise your child. My husband and I are really blessed and fortunate that we have many people that we could actually turn to and trust for something like that. In my world, I would choose my [adopted] sister because of her connection to Naleigh from their home country. My niece and nephew are both Korean. I would feel like that would be the best fit for her.

It's an interesting question, and it's a hard question, but I think people need to answer it. You would never want to leave that open-ended and have a child end up in foster care or orphaned if you didn't have to.

There are some funny scenes involving those 'edutainment' shows geared towards children. Do you think those types of shows are a valuable tool for educating and entertaining kids, or just plain creepy?

I'm somewhere in between. I would have said just plain creepy, and weird, and nonsensical, but then I started utilizing them the way most new parents do: to entertain a child during a meltdown, or distract a child when you have to go to the bathroom. I've seen my daughter learn things from these shows, like from "Yo Gabba Gabba!" Naleigh learned to dance. But I don't particularly love having those shows on repeat all day. I try to minimize it because I would go insane. [Laughs]

Do you have any friends who, if they put you into Holly's position, you'd refuse?

[Laughs] Ummmm ...

You don't have to name names...

None of my friends really have kids yet, except one. I can't imagine ever refusing. I'd probably be really resentful but I wouldn't refuse. [Laughs]

You'd do it, but you wouldn't like it

I don't know who would like it initially. You'd be like, 'Are you kidding me? Wow, you must have been desperate.' [Laughs] But that's why I love Holly and Messer. They sort of try to contain the resentment, but there's clearly several moments where they're like, 'What were they thinking?!'