By Rebecca Thomas
Entertainment reporter, BBC News
The Bielskis emerged at the end of the war having saved more than 1,200 Jews
Daniel Craig's latest movie Defiance sees the 007 star once again pushing himself to his physical limits.
There are guns, shooting and explosions, much as we have come to expect from the action hero.
But much more taxing were the sub-zero conditions in which the World War II Holocaust movie was filmed.
Nazi-occupied Belarus in 1941 is the setting for Defiance, which was shot in a winter-gripped forest in Lithuania.
"To keep warm we did a lot of drinking and I was wearing a little thermal on the sly but the cold definitely had an effect," says Craig.
"We were there 12 hours a day, six days a week and it got really cold, but there was something about that experience. Nobody did this for the money.
"We were all in it together and we all huddled. There was male and female bonding - but not in that way."
Thanks to 007, a lot more scripts are sent Craig's way, but he remains very picky about what he does.
Therefore hearing that his attachment to Defiance was instantaneous says a lot.
"This came along, I read it and immediately said, 'I want to make this movie. It's a story I want to tell,'" he says.
Defiance tells the incredible true-life tale of the Bielski brothers, Jewish working-class farmers from the remote countryside of what is now independent Belarus, but was then under Soviet control.
When the Nazis invaded and began executing Jews, the brothers - who had also lost family - led a small group to safety in the forests.
Their aim at first was purely survival and to exact vengeance wherever they could.
But as word of their daring spread and more and more of the persecuted sought them out, the priority became saving as many Jews as possible.
Under the leadership of elder brother Tuvia (Craig), the mission was so successful that by the end of the war more than 1,200 emerged from the deep forests.
Brutality of war
The story was published in 1993 after much research by Holocaust historian Dr Nechama Tec, but has remained largely unknown.
The film does not shy from showing the brutal reality of what the group's resistance involved - including in one instance the group murder of a German soldier.
And, suggests Craig, perhaps the difficulty of dealing with bloody memories has contributed to keeping the story buried.
Tuvia (Craig, left) and Zus (Schreiber) find they have conflicting ideas
"It was much more complicated than we can ever portray on screen.
"They did commit gruesome acts and one of the reasons the story has not been told is because these people wanted to forget," he says.
"But in those moments, it was very clear to me why - Tuvia was trying to keep spirits up and stop the group from infighting, so they had to be given their kill.
"He has responsibility for these people who are not on the face of it survivors. He has to teach and encourage them to survive and that's what I find so fascinating."
Less engaging for Craig, who left school at 16, was having to learn Russian - he says he is not a natural pupil.
"It was dreadful. I am just so bad at languages and so I had do it phonetically. I had a great coach who is also an actress, which helped, so I could sort of shout lines at her and then it was a leap of faith."
Joining Craig in Defiance as the other Bielski brothers are Liev Schreiber and Jamie Bell.
Schreiber plays the volatile Zus who struggles with what he considers to be Tuvia's idealism while Bell plays the young Asael, forced to grow up fast.
And for the Billy Elliot star, the making of Defiance also proved a quick learning curve.
"Action films and running around with guns doesn't come naturally to me," he says. "My instinct is to run the other way but that doesn't work on camera.
Jamie Bell says there was great camaraderie on set
"But I would look at Daniel, who does it brilliantly, making it look very fluid and dynamic and ask him for advice."
He says he had "instant chemistry" with Craig and Schreiber, which made acting as brothers all the more believable.
It also helped keep the sense of community authentic for the whole cast between takes.
"There were lots of jokes and lots of board games like backgammon," says Bell.
He also found he learned a lot more about World War II than he ever did at school.
Defiance is one of a slew of other new movies about events of the period, including The Reader and Valkyrie.
Director Ed Zwick thinks these films could be coming out now because of a "fin-de-siecle anxiety" to tell the story of World War II to young people before those who lived through it are gone.
But it still took several years for the Legends of a Fall and Glory director to get this "tough" story off the ground.
"It was a real struggle. We just couldn't get this made in the US," says Craig.
"Bond helped, but I think that if I had chosen to make a romantic comedy it would have easier to raise the money.
"But this is a tough story and so thank God for the film company that finally stepped in to help us out. The Bielskis [the descendants] have been to see it and have reacted very well, so I am very glad."
Defiance is now showing across the UK.