Oscar winner Geoffrey Rush didn't have to dig too deep to find emotion for a pivotal Nazi rally scene in new Holocaust movie The Book Thief - he was surrounded by Germans singing Adolf Hitler's banned national anthem.

The film was shot on location in Germany and one scene really upset Rush, who plays a father protecting a Jew from the Nazis, after the cast and crew took over a small town near the Polish border.

He explains, "The most telling moment was when we recorded the Uber Alles, which was the national anthem at the time. We did it with about 450 extras. Our wonderful second assistant was German and we had musical arrangers who had to teach all the extras the verses that had been banned since 1946. They didn't know them.

"There were people singing that song (in the film) as best as they could because they were directed to sing it with some pride. It's hard for people to sing something that they're alien with and don't believe in. Some of them did it convincingly. The thing that touched me most of all was the crew, which was almost completely German, including our director of photography, and I looked around and there were tears in their eyes because it's so painful for them to sing... There's still a sense of some of the shame; they still felt for somehow feeling responsible still to this day for those terrible things that happened. It was an emotional time.

"Also the Swastika (symbol) understandably is banned in Germany, so when we dressed the town square in hundreds of Swastikas, it was really quite powerful for the crew. There's an awful lot of philosophical debate over second and third generations about what it means to different people."