Isaacs suffered 'bleak time' for Good
The Harry Potter star plays the best friend of a man who becomes a Nazi in 1930s Germany - but the emotional intensity of his part affected Isaacs.
He tells Total Film magazine, "Making Good was a very bleak time for me because I felt like I had a responsibility to revisit the Holocaust so I read only diaries from the time.
"It gave me an insight into the many rationalisations that people used to get through the day."
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