After giving birth to her second child, it appears that Reese Witherspoon is keeping her kids in mind when choosing acting roles. In the new film Just Like Heaven, she plays a work-obsessed nurse who has a possibly life-ending accident. She spends most of the movie as a spirit, able to be seen only by the new tenant of her old apartment. Witherspoon says that having kids changed her view of her career.

"As soon as I became a mother," she says, "I felt the responsibility of being a role model. That carries over into my film choices."

In this film, Witherspoon’s character, Elizabeth, gets the gift of seeing her life from the outside looking in. In the process, she gets to know David (Mark Ruffalo), a lonely man who has recently lost his wife, and the only person who can see her.

Witherspoon and many of the people involved in the film liked how it wasn’t a typical romantic comedy. "I read lots of romantic comedy scripts," Witherspoon says. "This one had a nice spiritual message. I like the life quality. She could see life for what it was. The second chance interested me."

Ruffalo also liked how it has a different feel. "It’s the anti-romantic comedy a bit," he says. "The romance is handled realistically. And it’s funny and romantic, unlike lots of romantic comedies."

The relationship between the two leads is different from the normal lovers’ bond that exists in many romantic comedies. In fact, for much of the movie, Elizabeth and David really get on each other’s nerves.

"I love having an antagonistic relationship at the beginning," Witherspoon says. "It’s like the classic Katharine Hepburn and Spencer Tracy movies."

According to director Mark Waters (Freaky Friday, Mean Girls), "Reese isn’t the girl next door, and Mark brings that alt-rock energy. They just go at it for the first half."

This film presented quite a unique challenge for Ruffalo, who was recently seen as Jamie Foxx’s cop friend in Collateral. Half the time during shooting, he had to act without Witherspoon there, since that is the way everyone else in the film sees it. Ruffalo says it was difficult at first – the filmmakers used a ping-pong ball for her eye line – but eventually he got used to it.

"Naturally, after awhile, I made that transition," he says. "She’s right here," he adds, motioning with a smile, to Witherspoon’s exact height.

Witherspoon has another high profile role coming up in the fall where she’ll play June Carter Cash in the new Johnny Cash biopic, Walk the Line. She's also had a recent run-in with the paparazzi, for which she took them to court.

"Illegal behavior is not acceptable," Witherspoon says. "But I believe in the first amendment, and freedom of speech. They have the right to take pictures of public figures. I have seen much more respect. There is some change."

She says she does not read the tabloids. Unfortunately, she is a target, in part due to her movie star husband, Ryan Phillippe.

"They can be hurtful," she says. "Why ruin your day on something the dog’s going to pee on tomorrow?"

In terms of real news, though, the filmmakers might have cause to worry about the connection between this film and the recent Terri Schiavo story. The issue of life support becomes a big theme in Just Like Heaven. However, the film is based on a book and it was already in post-production when the Schiavo story broke.

Another important theme in the film is the notion of when work becomes too much in a person’s life. Elizabeth works lengthy hours and seemingly doesn’t have time for anything else, including a companion. Witherspoon says she can see where Elizabeth is coming from.

"I could relate to Elizabeth’s work ethic," she says. "I’ve had moments where I felt like I was working all day. It’s important to take breaks. I like to just lie on the floor with my dogs."

After seeing Michael Bay’s action film The Island fail to grab many viewers, DreamWorks is hoping these themes within this unique type of romantic comedy will strike a nerve with a different type of audience. Combined with the star power involved, Just Like Heaven just might be one of the big hits of the season.

Just Like Heaven releases in theaters Sept. 16.