The 43-year-old, who has sons Dashiell, 11, Roman, eight, and Ignatius, four, with husband Andrew Upton, lets her kids come backstage, reported Contactmusic.
"It's like being a circus family, in the way doctors and lawyers don't hide their children from what they do. It's a pretty exciting place backstage and I filmed for eight days on 'The Hobbit' and it was so exciting for them because they saw the 3D cameras, they watched all the stunt guys and could see how the film was put together, so it was good," she said.
"I haven't made a film for quite a long time, because I've been doing theatre, but it gets to the point where they are not so portable, so you make the choice to do less. It's been great to be in Australia, but they come backstage.