Angelina Jolie directing Unbroken to inspire her sons

Angelina Jolie decided to step behind the camera once again to direct a biopic of Olympian-turned-World War II prisoner Louis Zamperini to inspire her three sons.

The Salt star has six children with her partner Brad Pitt and hopes her new project Unbroken will be a positive influence on her sons Maddox, 12, Pax, nine, and Knox, who turns five next month (12Jul13).

The movie is based on Laura Hillenbrand's book about Zamperini, a long distance runner who competed at the 1936 Olympics in Berlin, Germany.

After World War II broke out, Zamperini enlisted in the Army, only to be captured by the Japanese and held prisoner.

Jolie tells the Daily Mail, "(Zamperini) was captured during World War II and held by the Japanese. His family and the authorities thought he was dead, but he survived.

"It's a story of courage and I want to make it for my sons because it's an example of sacrifice and survival against all odds. They'll learn something from it."

The actress added she is currently working on the script and casting for the movie but shooting in Hawaii will not take place until the end of the year (13).

Jolie previously directed the hardhitting 2011 movie In the Land of Blood and Honey.