Hepburn's secret past fighting Nazis

1961: Belgian-born actor Audrey Hepburn (1929 - 1993). Photo / Getty

Beloved actress Audrey Hepburn worked directly under Dutch Resistance leaders to help defeat the Nazis, a new book reveals.

In Dutch Girl: Audrey Hepburn and World War II, author Robert Matzen writes of his proof that the Breakfast at Tiffany's star was involved in fighting the Nazis during World War II according to DailyMail.

British actress and dancer Audrey Hepburn (1929 - 1993) rehearsing at the barre, circa 1950. Photo / Getty

Born in 1929 in Belgium and relocating to Holland at the start of the war in 1939, Hepburn was traumatized by the murder of her uncle Count Otto van Limburg Stirum.

In Matzen's book, due to release in April, he reveals the discovery of a 188-page diary Hepburn's uncle Otto wrote during the four months he was imprisoned by the Nazis before his death in 1942.

Hepburn's son, Luca Dotti, says Matzen's book solves mysteries he's had about his mother.

'I now understand why the words Good and Evil, and Love and Mercy were so fundamental in her own narrative. Why she was open about certain facts and why she kept so many others in a secluded area of her being,' Dotti writes in the forward.

Matzen says Hepburn worked in the Dutch Resistance as a doctor's assistant during the Bridge Too Far battle of Arnhem in 1944.

For the first two years of the war, Hepburn had to contend with the fact that her father was a Nazi agent and her mother was pro-Nazi.

She was a pre-teen ballerina in England before being relocated the Holland and then became Arnhem's most famous young ballerina.

The highly-anticipated book claims to have 'Audrey's own reminiscences, new interviews with people who knew her in the war, wartime diaries, and research in classified Dutch archives.'

The detail will shed light on the untold story of the star the world grew to love as she battled through World War II.

Audrey Hepburn Sitting in an Armchair. Photo / Getty

'When my mother talked about herself and what life taught her, Hollywood was the missing guest,' Dotti writes in the forward.

'Instead of naming famed Beverly Hills locations, she gave us obscure and sometimes unpronounceable Dutch ones. Red-carpet recollections were replaced by Second World War episodes that she was able to transform into children's tales,' he adds.

Never-before-seen color and black and white photos are also included in a separate section of the book - many of which are from Hepburn's personal collection .