Three of Angelina Jolie and Brad Pitt's six children have landed parts in their mother's new movie.

The high profile couple's son Pax, eight, and daughter Zahara, seven, have reportedly been signed up to appear in their first movie 'Maleficent' alongside 37-year-old Angelina and their four-year-old sister Vivienne Jolie-Pitt.

A source told USMagazine.com: "They have smaller parts."

But the couple's eldest daughter Shiloh, who previously appeared alongside her father in acclaimed 2008 movie 'The Curious Case of Benjamin Button', is said to have turned down an opportunity to be in the new Disney film.

Related: Jolie, Pitt daughter to make film debut

The source said: "Shiloh was supposed to be in it, too, but she was bored and not in the mood during the day her part was supposed to happen, so she ended up not being in the film."

News that the children will appear in the fantasy fairy-tale comes just two months after a spokesperson for the couple confirmed their youngest daughter Vivienne would play a younger version of Elle Fanning's character Princess Aurora in the live-action film.

A source has revealed that the children's roles do not involve speaking and they are merely walk-on players in the christening scene when a curse is placed upon the child.

Filming for the movie began in London in and Angelina previously said her children were "very happy" she was appearing in it.