If "Silver Linings Playbook," about a bipolar man returning to his family after a stint in a mental institution, rings with authenticity, it may have something to do with the director and one of the stars of the film.
Director David O. Russell has talked openly about how much he wanted to make this film because of his experiences raising his bipolar son, Matthew. "It's personal to me, because I've lived through some of these experiences with a son," Russell told The Hollywood Reporter in December, during a videotaped Q&A with some of the film's stars and producers.
In fact, Russell's son makes an appearance in the film, which has been nominated for eight Academy Awards. He's the nosy neighbor who tries to interview Bradley Cooper's character, Pat, for a project on mental illness. "That's him who rings the doorbell and who he [Robert De Niro] chases in his pajamas."
Russell's son was diagnosed with autism as a toddler, and over the years, that diagnosis has been changed to a bipolar-obsessive compulsive disorder hybrid.
The film also struck a deep chord with De Niro, who plays Pat's father in the film. Recently, discussing the film on Katie Couric's show, the "Raging Bull" actor choked up.
"I don't like to get emotional, but I know exactly what [Russell] goes through," the 69-year-old Oscar winner -- who has four sons of his own -- said, starting and stopping his words while appearing to be holding back tears.
It's not clear to what extent De Niro relates. The legendary actor is tight-lipped about his personal life. His rep did not respond to ABCNews.com's request for comment.
The father of six went on to tell Couric, "If you're a father, you certainly understand what it's like to go through the worry about your kids, especially if they've got issues like Bradley's character has. Sometimes it can be overwhelming. It can be nightmarish and upsetting. There's nothing much you can do but deal with it."
"Silver Linings Playbook" has been one of the surprise hits of the year, racking up Oscar nominations for best picture, director and screenplay, as well as best actor for Cooper and best actress for Jennifer Lawrence, who plays his love interest. De Niro also earned a best supporting actor nod and Jacki Weaver picked up a best actress nod for her role as his wife.
Couric's show was not the first time De Niro was overcome with emotion while discussing the film.
"When I went to talk to him about the script and how personal it was to me and he met my son ... I thought he was having hay fever, and then I realized, no, he was actually crying," Russell told The Hollywood Reporter. "That was a very powerful experience for me, to sit with him and watch him cry."
"I thought two things: that I can't believe this is happening and ... I think this means maybe he's going to do the film. I think if you feel something at a personal level, then you want to do it," Russell added.
After that meeting, Russell recalled to THR, that De Niro told his agent: "Make this happen."
On the set, De Niro would arrive early with all of his lines memorized.
"For someone who has accomplished so much, who has nothing to prove, who has such a large life, he couldn't have been more present," Russell told THR. "His presence made clear that he loves what he does, as an actor, no matter how many years later."
De Niro deflected the attention away from him. "Working with David was a special experience, and working with this kind of material with his sensibility was fun and good," the actor said during the Q&A. "I'm very happy that it turned out this way."
"We're both fathers and I think that's a very strong energy that was in the film -- what's it's like to be a father who wants to see a kid back on his feet," Russell said.