A lost documentary Alfred Hitchcock made about the horrors of the Nazi concentration camps during World War Two has finally reached screens thanks to movie mogul Brett Ratner.

The Rush Hour director is the unlikely producer of the powerful new film, which Hitchcock helped compile at the end of the war.

The footage, shot by specially-trained soldiers to document the atrocities uncovered by ­the Allied forces in the prison camps, was intended to be used as evidence against German leaders facing war crimes.

But before the legendary filmmaker completed the hard-hitting German Concentration Camps Factual Survey, the project was shut down as U.K. officials attempted to ally with Germany against the Soviet Union.

Ratner's documentary, titled Night Will Fall, chronicles the film's history and features interviews with some of the men who shot it. Narrated by Helena Bonham Carter, it was screened at the Museum of Jewish Heritage in New York on Thursday (15Jan15), and a clearly emotional Ratner fought back tears as he introduced the film.

The film will debut on HBO at the end of the month (Jan15) to coincide with the 70th anniversary of Auschwitz's liberation.

Auschwitz was among the worst of the concentration camps, where Nazis tortured and killed Jews.