Christian Bale makes his co-stars ''better'' actors, according to Casey Affleck.

The 'Out of the Furnace' stars enjoyed working together on their new movie and Affleck claims his on-screen brother raised the level of talent on set with his gripping performance.

He explained: ''It's awkward to say because he's sitting right there, but I think he just makes everyone better around him and is an anchor of reality. If someone's in a scene with you and they're listening to what you say and they're looking at you in that way, then you're having a real conversation and there are real feelings and relationships.

''On the very first day or two, we were doing those scenes [in a prison] and Christian was very patient. I did and said some things that just immediately made me trust him and then it just went smoothly from there.''

Meanwhile, Bale has revealed he insisted on Affleck - younger brother of actor-and-director Ben Affleck - being cast in the project and even threatened to quit if he wasn't.

He told ''I'd been saying, 'We want Casey for the role.' There were a lot of conversations about that and [director] Scott [Cooper] and I just kept saying it, and eventually we were saying, 'We're not doing it without Casey.' ''