The 39-year-old actress said while shooting for a violent scene for the movie she hit Cooper a bit too hard, reported Contactmusic.
"There's a scene where I was supposed to hit Bradley. I wasn't hitting him hard enough and David kept yelling, 'Hit him. Hit him.' And Bradley kept yelling, 'C'mon, hit me, hit me!' So I finally hit him, but I whacked him so hard that his face began to swell and I was crying because I thought I'd given him a black eye," she said.
"He will do anything. Bradley's the cheerleader on set. He's like, 'Let's do this, come on, everybody!' He's my hero in this film," she said.
Directed by David O Russell, 'American Hustle' has bagged 10 Academy Award nominations, including Best Picture, Best Director, and Best Original Screenplay among others.