Harrison Cheung, Bale's co-worker for a decade, has written the book Christian Bale - The Inside Story of the Darkest Batman, which reveals his time spent with the Dark Knight Rises star.
Cheung claims that Bale had often cited Leonardo DiCaprio as his nemesis when it came to landing big movie roles, as the Departed actor would often land parts that he had also applied for.
"DiCaprio. The name burned Christian like a branding iron," Cheung writes.
"Over the years, Christian had lost This Boy's Life and What's Eating Gilbert Grape to DiCaprio. Christian had read for the part of Mercutio in Romeo & Juliet but was told that they had decided to cast an African-American in the part instead.
"Christian too had gone up for the part of Jack Dawson in Titanic but was told that James Cameron didn't want two British lead actors playing the two leads who were both supposed to be American."
Bale later had to fight off competition with DiCaprio and Ewan McGregor for the lead role in American Psycho, a part which he reportedly became "obsessed" with.
One friend told the author: "It was really creepy. He would call up and go, 'It'sssssssss Patrick' as soon as you answered the phone in that perfect American accent."
Cheung also claimed that Bale would often make fans cry if they disturbed him during his personal time.
"Pity the fan who recognised Christian at a restaurant," he explained.
"He refused to sign autographs while he was seated. He would lecture little girls about being rude and intrusive until tears streamed down their faces and their parents tugged them away from our table."
Christian Bale will return as Bruce Wayne in The Dark Knight Rises, to be released on July 20.
Watch the trailer for The Dark Knight Rises below: