Brad and Angelina hit Cannes for Pearl film

Jolie is expected to be joined by the widow of U.S. journalist Daniel Pearl, Mariane, whom she plays in A Mighty Heart.

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On the red carpet: Angelina Jolie and Brad Pitt arrive at the world premiere of 'A Mighty Heart' in Cannes

Angelina's tattoos have a special meaning to her

The biopic, directed by British filmmaker Michael Winterbottom, has been jointly produced with Pitt's film company.

It is about the murder of Pearl by Islamic fundamentalists in Pakistan five years ago.

Pearl, the South Asia bureau chief for the Wall Street Journal, while researching a story on British shoe bomber Richard Reid in Karachi.

Mariane wrote about his disappearance, the intense effort to find him and his murderer in her memoir A Mighty Heart: The Brave Life and Death of My Husband Danny Pearl.

Mariane was six months' pregnant when the ordeal began and she wrote the book to introduce her son to the father he would never meet. Mariane was pregnant.

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Brad Pitt leaves Prague on with children Zahara (left) and Pax before flying to France with his partner Angelina Jolie

It has its world premiere on Monday night but, because of the sensitivity of its subject matter, its makers have decided not to enter it for competition at Cannes.

Jolie, 31, has outlawed a post-show party, deeming it inappropriate to celebrate.

The biggest premiere of the festival is expected on Thursday when Pitt will promote Ocean's Thirteen.

Speaking to reporters, Ms Jolie said: "For me, so much of why this film was important to do is because I highly doubt there is anybody in this room who has more reason to hold hate inside herself than Mariane, and she doesn't.

"That is, I think, a lesson for all of us." The film begins on the last day the Pearls spent together in Pakistan, where they were both on assignment as reporters.

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Beautiful people: Brad and Angelina at the International Film Festival in Cannes for the film A Mighty Heart

Angelina has outlawed a post-show party, deeming it inappropriate to celebrate

When he disappeared, Mariane Pearl was deeply involved in the search to find him. Pearl said she got in touch with Jolie after reading a magazine interview with her and being struck by the feeling they could be friends.

She asked Jolie to play her in the film adaptation of her memoir 'A Mighty Heart,' and said their friendship grew over the course of the project.

"I think about the fact that my son will see the film one day, and this is a great moment of pain for me," Pearl said. "And this role was played by somebody who loves me, and it means a lot to me."