Today on Katie, Silver Linings Playbook cast members Robert DeNiro and Bradley Cooper joined director David O’Russell for an interview with host Katie Couric which ended up getting pretty heavy.

The film of course tackles the subject of bipolar disorder which hits very close to home for Russell and also for DeNiro. The actor got emotional when Katie asked him, “Did you feel a greater responsibility about doing a film that [director David O. Russell] had so much personally invested in?” Katie was referring to the fact that Russell’s own son has a mood disorder.

De Niro began to repsond and said, “Oh, of course, I understand what he…” It was at this point that he got too choked up to continue. Couric passed him a tissue and Cooper put his hand on DeNiro’s shoulder. “I don’t like to get emotional, but I know exactly what he goes through,” he continued, gesturing over to Russell.

It’s really interesting to learn why the director wanted to do the film and also why DeNiro became emotionally invested in his role. Watch the touching interview below.

‘Silver Linings Playbook’ Cast On ‘Katie’