The 39-year-old actress was not doing it well enough initially, but finally succeeded after being encouraged by Cooper and her director David O Russell, reported Contactmusic.
However, it gave him swelling and he needed an ice pack to ease the pain.
"I believe you can accomplish something without hurting someone, so I kept hitting him and I guess it wasn't reading as hard enough. So David's yelling, 'Hit him, hit him', and Bradley's yelling, 'Hit me, hit me', So I did. And his face started swelling," Adams said.