Angelina Jolie waves as she arrives with Brad Pitt for a photocall for British director Michael Winterbottom's film "A Mighty Heart" at the 60th Cannes Film Festival May 21, 2007. [Reuters]

It is her children that keep Angelina Jolie's feet firmly on the ground while the paparazzi follow her every move, and motherhood helped the star prepare for her role as the pregnant wife of slain reporter Daniel Pearl.

The 31-year-old actress, who with her off-screen companion Brad Pitt has formed the celebrity super-couple dubbed "Brangelina," plays Mariane Pearl, wife of the Wall Street Journal journalist who was kidnapped and beheaded by Islamic militants in Pakistan in 2002.

Mariane Pearl, who wrote a book about her experiences, was about six months pregnant at the time, and Jolie filmed "A Mighty Heart" not long after she gave birth to her daughter Shiloh.

Jolie and Pitt, 43, also have three adopted children, from Cambodia, Ethiopia and Vietnam.

"My children help me keep perspective," Jolie told Reuters in an interview on Wednesday just outside Cannes, where the movie had its world premiere.

"The world forms opinions and has a view and does tabloid things and fortunately none of that is inside my home," she said at the exclusive Du Cap hotel. "I (am) focused on getting the kids to school, I'm focused on the balance of all the children."

Critics have praised Jolie for her portrayal of a woman who desperately seeks her husband through phone and e-mail trails and in the teeming city of Karachi, a hotbed of militancy just after the 9/11 attacks.

MEMORIES OF NAMIBIA

Jolie was in Namibia when discussing the script with Mariane Pearl and British director Michael Winterbottom as she prepared to give birth to Shiloh.

"We were all in Namibia and I was six months pregnant, and I remember seeing Mariane and talking to her about being pregnant.

"At the same time I would go home, sit and lay next to Brad, and he would put his hand on my stomach and we would talk about the hospital and the baby and were so excited together.

"To know that's what they took away from her at that time infuriated me, it made me so, so upset."

She added that Pearl had no time for letting her "emotions run wild," but added: "But thank God she was pregnant, because she has Danny in (their son) Adam ... he is Adam."

Jolie said "A Mighty Heart," which Pitt co-produced, did not signal a shift away from comic or action roles for which she is best known, even though she won an Oscar for "Girl, Interrupted" set in a mental institution.

"I think people think that now I'm just trying to be serious and do very serious films.

"But the reality is I'm playing an assassin now in a movie and my little boys think it's really cool and I'm going to do a cartoon next where I'm a tiger and ... that's why I get kudos in my house."

The star of box-office hits like "Mr. & Mrs. Smith," in which she played alongside Pitt, Jolie said she had been gripped by Pearl's tragedy when it played out before the media.

The film still had relevance today, however, for its message of tolerance.

"This woman, who has the greatest reason to be just blinded by hate, is speaking up very strongly and saying we have got to have a dialogue, we have got to continue to find ways to relate to each other and not just focus on differences."

Jolie said she would continue to take time off in between filming to be with her family, and that she and Pitt took turns acting in movies.