Don’t be fooled by the title. “Brothers” may emphasize the dynamic between make-pop-proud elder son Tobey Maguire and black sheep Jake Gyllenhaal, but it’s Natalie Portman’s character who finds herself at the center of that equation. Her husband (Maguire) is shot down in Afghanistan, putting Portman’s would-be widow through a gauntlet of grief, only to have her world turned upside-down again when he returns.

“It was really helpful to speak to military wives to see what their lives are like,” Portman says. “They have this sense of mortality at an early age that civilians don’t normally have to deal with.”

And though writer David Benioff shaved about 10 years off the characters vis a vis their equivalents in the 2005 Danish film “Brodre” on which “Brothers” is based, Portman really responded to the maturity of her character.

The challenge, it turned out, was shooting during the 2007 WGA writers strike. Portman and the cast had about one week to talk through the characters with Benioff and director Jim Sheridan before shooting, but when it came time to film difficult scenes, such as the park-bench encounter where Portman and Maguire trade confessions, the actors had to find the answers for themselves.

“In that scene, we just didn’t have the right words. It was really scary because we talked about it for five hours without shooting anything. Jim just gave us this little bubble to work on it on-set. With such extreme situations, it’s hard to find the words that are authentic and don’t make it feel like a melodrama.”