De Niro has an uncredited cameo in the movie and director David O. Russell admits he knew he'd perfected Bale's podgy, balding look when the movie great asked the filmmaker who the overweight guy was.
Russell tells Wenn, "We wanted to do something he'd never done before. When he met the whole cast he shook their hands and said, 'Who's that guy?' And I said, 'You just met him, that's Christian Bale'. He goes, 'Wow, he looks so different. He looks great!' He didn't realise he just met him and I had to reintroduce them."
The director admits it was a pleasure to work with Silver Linings Playbook star De Niro again: "He's someone I've known over 10 years and got very close to making Silver Linings with him and he's also close to Bradley (Cooper). We had endless conversations about the character and he loved that this man spoke Arabic, which happens to be one of the true things in the story - there was a mobster who spoke Arabic and flummoxed this group. We based him on a collection of gangsters from New Jersey."