Christian Bale is one of those actors who loses himself in whatever role he is playing. When, in 2004, he took on the part of Trevor Reznik in the psychological thriller The Machinist, he embarked on a crash diet - reportedly just coffee and apples - to lose the more than 27kg he needed to most effectively play the emaciated protagonist.
And director Michael Mann is known to be a stickler for details; when he was shooting The Insider with Russell Crowe in 1999, he deliberately placed a small smudge on the glasses Crowe's character wore, in order to impart the kind of subliminal information about him that only an artistic genius could come up with.
Put Bale and Mann together in a project, and the result is attention-to-detail overdrive, an intensity that goes way beyond the norm - even for a fact-based film such as Public Enemies. 'He behaves like a detective,' says the 35-year-old Welsh-born Bale of his director. 'He leaves no stone unturned.'
As a result, Bale wasn't surprised when, prior to beginning production, he opened his door one day to find boxes filled with information about Melvin Purvis, the driven and acclaimed FBI agent who, in 1933, was entrusted with the task of capturing John Dillinger (played here by Johnny Depp), a bank robber who lived about the time of the Great Depression and became an American icon.
Bale, at Mann's behest, found himself studying everything that the director could find on Purvis and the time in which he lived. Because even though the movie is about Dillinger, and nobody could fault the director for taking some creative licence with a secondary character, Mann and Bale did what they always do on every project - they immersed themselves fully in the task at hand. They went on a fact-finding trip to FBI headquarters in Quantico, Virginia, and spent time with Purvis' son, Alston. Because Purvis died in 1960, and there was no recording in existence of his voice, Bale studied Alston's southern drawl.
'We visited various individuals we felt could give us some insight into the family life and background of Purvis,' says the actor, who spent time at the late agent's home in South Carolina where he met with surviving family members and friends.