PHOTO: Christian Bale Reveals Weight Gain, Beer Belly in AmericanHustle Trailer

Halt! Who goes there? Christian Bale underwent yet another body transformation for his role in the upcoming David O. Russell film American Hustle -- but this time, the versatile actor gained weight instead of losing it. 

In the newly released trailer for the 70s-era flick, Bale, 39, sports an impressive goatee, a full head of shaggy shoulder-length hair and, most notably, a fuller figure and beer belly.

"He wasn't necessarily in good shape, and he had this combover that was…elaborate," Amy Adams says in voiceover for the clip. In the film, Adams plays Bale's mistress (a sultry Jennifer Lawrence plays his long-suffering wife). "But he had this confidence that drew me to him."

The film has an all-star roster, including Bradley Cooper, Jeremy Renner, and Louis CK.

Bale has long been known in the industry for his commitment to his roles, which have included numerous demanding weight gains and losses in the past. For 2010's The Fighter, Bale famously shed major pounds in order to play Dicky Eklund, a welterweight who also happened to be a crackhead. He then bulked up to play Bruce Wayne in 2012's The Dark Knight 

Perhaps most memorably, in 2004, the Welsh actor made headlines for shedding 70 pounds to play the emaciated, troubled lead in The Machinist.

"Believe me, I don't go looking for these things," Bale told Access Hollywood in a 2010 interview. "If it does happen, it's like, 'Oh damn, I have to do that again, because I just tend to fall for the movie, the character, and then I'll realize, 'Oh man, I gotta do that.'"