'American Hustle' Cast on Their Transformations, the Art of the Con and More

Dec. 10, 2013— -- "Silver Linings Playbook" director David O. Russell continues to bring deeply conflicted characters and gleeful chaos to the big screen in his latest dark comedy "American Hustle." The film follows a busted con artist couple, played by Amy Adams and Christian Bale, forced to work their magic for an FBI agent, Bradley Cooper, who's looking to capture political corruption on tape.

Whether a manipulator or an intended mark, each character is ready to con their way to happiness throughout the film, but as a testament to life, Russell requires each to confront the universal truth that nothing, and no one, is what or they appear to be.

But before this all-star cast could tackle Russell's truth, they each had to go through a labor-intensive transformation.

Bale packed on nearly 50 pounds for the role, and even shaved a part of his head in pursuit of an over-the-top comb over.

The actor, who famously lost more than 60 pounds for his role in "The Machinist," said he gained the weight by "eating crap" for a couple of months.

"It's a lot of fun for about two weeks and then your body starts to say, 'Please, please don't do this anymore,'" Bale told "Nightline."

While Bale seems to have effortlessly lost the 50 pounds, he confesses it happened "much more slowly than I would've done 10 years ago."

For Adams' stripper turned grifter role, the actress had to be comfortable with showing some serious skin.

"It becomes a part of her arsenal of manipulation," Adams said.

The actress shares that when donning her character's dresses with plunging necklines "there was a sort of confidence that happened because your posture has to change to sort of keep everything in place. So it's not until I see the posters that I think, yeah, that's kind of revealing."

Cooper, a former "Sexiest Man Alive," suggested his character should sport an intense curled hairdo "because we kind of wanted to make him look different from me."

Unbeknownst to Cooper at the time, the style would take three hours to achieve every day and would require early trips to the makeup trailer.

"American Hustle" bases its story as loosely as Cooper's root perm on the Abscam stings of the 1970s, in which the FBI taped congressmen taking illegal payments via a fake sheikh and conman Melvin Weinberg, from whom Bale learned the art of deception.

Bale says Weinberg taught him what the art of the con means.

"You believe what you believe as you're doing it. Otherwise no one else is ever going to....'To be a conman, you got to have a big set of balls,' you know?" Bale said.

Life on set was a familiarly unconventional experience for the actors as Russell reteamed with talent who worked with him on previous projects and were familiar with his improvisational style.

"I've only been on two of his sets...but both have the exact same energy, which is very alive. Anything can happen. And you better have slept eight hours," Cooper said.

"A lot of actors like to be very controlled, know exactly what's happening," Bale added. "And I'm not that kind of actor. I like it to be very spontaneous."

"I think that you really strike gold sometimes when you have that attitude," Bale said.