'Joy' Stars Jennifer Lawrence, Bradley Cooper Reveal Secrets Behind Their On-Screen Chemistry

— -- Jennifer Lawrence and Bradley Cooper are no strangers to sharing the big screen.

Now, they are teaming up for a third time with co-star Robert De Niro and director David O. Russell for the movie "Joy."

"When we met her, she was 20 years old on 'Silver Linings Playbook,'" Russell told “20/20” co-anchor Elizabeth Vargas. "She had not had ‘Hunger Games’ yet. [She] asked Robert De Niro what it was like to be recognized on the street."

Loosely inspired by the real-life home shopping entrepreneur and inventor Joy Mangano, the film features Lawrence co-starring alongside Cooper for the first time since 2013's "American Hustle."

"I feel very safe [with Lawrence]," Cooper, 40, said. "I can turn my brain off as an actor. I think, having to learn that dance routine [in 2012’s ‘Silver Linings Playbook’], we really didn't know each other at all. Talk about being vulnerable with somebody."

Lawrence, who snagged a Golden Globe nomination for her role in "Joy," agreed that her on-screen chemistry with Cooper comes naturally.

"David made us a bizarre kind of form of siblings, in a way," Lawrence, 25, said.

"Joy" will be released in theaters Christmas day.