Bradley Cooper fought back tears as he paid tribute to his Silver Linings Playbook co-star Matthew Russell because his bipolar struggles inspired his director father David O. Russell to make the film.

Cooper portrays a bipolar sufferer in the Oscar-nominated film and he admits some scenes with young Russell, who plays a nosy neighbour in the movie, were tough to shoot.

Fighting back tears during a taped interview with U.S. talk show host Katie Couric on Friday (01Feb13), the choked up actor says, "I couldn't keep it together."

Director Russell was clear about the importance of the film when he cast Cooper as his leading man, revealing, "I wanted to tell a story that would make my son feel like he's part of the world and that he's in the world."

The Silver Linings Playbook special will air on Couric's show on Monday (04Feb13).