The five-months pregnant Kidman, a mother of two, was in Japan to promote her latest big-budget fantasy film The Golden Compass and said she had deliberately chosen the child-friendly script.

"My Bella and Connor are 13 and 15. So they have seen the film and they loved it...my child inside won't see the film for a long time," she told a news conference.

"But I think once you have children you want to balance the work you do because they give up so much of you to your work. So occasionally you want to make films that they can take their friends to, they can go to the premiere of, that they celebrate," she added."

Directed by Chris Weitz, The Golden Compass also features newcomer actress Dakota Blue Richards who beat off 10,000 girls to play the film's central role of Lyra.

The New Line Cinema film, an adaptation of Philip Pullman's novel Northern Lights, has been an international hit with worldwide sales to date of about $300 million. New Line is a unit of Time Warner Inc.

Kidman, 40, was due to start filming the post-World War Two drama The Reader in early 2008, directed by Stephen Daldry who made The Hours which won Kidman her 2003 best actress Oscar.

But she has withdrawn from The Reader due to her pregnancy. Dressed in a see-through Prada dress, a radiant Kidman told reporters she was happy that way.

"I have been to Tokyo quite a few times. But this is the first time I have been to Tokyo pregnant. I am very glad to be here this way," she said.