 A race-based controversy arose over the decision to make the majority of the characters white Americans, even though the main players in the book "Bringing Down the House", upon which the film "21" is based, were mainly Asian-Americans.The lead role was given to London-born Jim Sturgess, who required a dialect coach to speak with an American accent.Jeff Ma, who was the real-life inspiration for the character Ben Campbell and served as a consultant on the film, was attacked as being a "race traitor" on several blogs for not insisting that his character be Asian-American.