The actor, who plays Gamemaker Seneca Crane in the film, revealed that his character's sculpted facial hair was all his own, forcing him to undertake day-to-day errands with the unusual shaving job.
"Yeah, I went to Target all the time - I had to buy baby formula with this beard!" Bentley told New York Magazine.
"But no-one ever reacted to it," he continued. "Maybe they were being polite. Maybe it was that controlled Southern thing, and they just wouldn't say anything."
Bentley went on to say that they experimented with the beard before settling on the one that is seen in the movie.
"The first one was a bit more dramatic than that, and a bit more sinister," he explained. The hooks were just a little bigger and sharper. [Director] Gary [Ross] loved it, but he wanted to tone it down a little bit because in the end, Seneca's not the devil.
"He's not metaphysical - he's a human being and he's trying to do a job," he continued. "He's evil and he's ignorant to the fact that he's creating consequences, that people are actually paying for this, but he's not the actual bad guy, I guess."
Bentley recently confessed that he is ready for a career comeback after struggling with drug and alcohol addiction for years.
> The Hunger Games wins US box office with $155m - top ten in full