For a drama about a childhood filled with hunger, homelessness and poverty, the red carpet at the Wednesday night New York screening of “The Glass Castle” was a really happy one, with big laughs from the stars and squeals of excitement from the cast of kids.

The youngest stars of the bestselling memoir-turned-movie, Olivia Kate Rice, Sadie Sink and Chandler Head, exchanged hugs, posed for selfies, and jumped for joy, along with stars Brie Larson, Naomi Watts and author Jeannette Walls. The whole event seemed like a family reunion.

“This cast really became a family and that is a really beautiful thing,” said Walls, whose 2005 memoir of the same name served as the source material for the film. “The thing with each of these great performances was that there was a lot of trust happening.” Walls is well-known for her stint as a gossip columnist, and now lives with her husband and mother on a farm outside Culpeper, Va.

The film, directed by Destin Daniel Cretton, follows the Walls’ unconventional, nomadic upbringing with their alcoholic father Rex, played by Woody Harrelson, and artist mother Rose Mary, performed by Watts. The four children eventually hatch a plan and start saving to make a move to New York.

Ella Anderson, who plays the younger version of Jeannette in the film, said getting to work with Larson was an especially important thing to her.

“I learned a lot from Brie. She taught me how to get more out my character and every moment watching her I just took it in,” she said. “The heavy subject didn’t mean the cast didn’t have a blast making the movie.”

Cretton explained the family vibe on set came naturally from the team who seemed to just get along well, but also were dedicated to telling the story accurately.

“Walls’ description of her family was so honest and I found it really affecting how much love she sewed into every moment — even the ones that are really dark,” said Cretton. “You can tell that they’re so painful because the characters do love one another and don’t know how to express it.”

Max Greenfield, best known for “New Girl,” plays Walls’ well-meaning, but goofball fiancé in the film. He said getting to join the cast was an unexpected pleasure.

“I read the script and knew Destin and Brie were involved so I sort of would have done anything to be a part of it at that point, but I auditioned and read with Brie and I sort of figured if I didn’t get it, then at least I had that experience,” he laughed.

Now with the role under his belt, Greenfield joked he can add getting squarely punched by Harrelson to his resume. “Shooting that arm wrestling scene was just so much fun. We were all in it and there’s just a lot of energy and working with Woody was a real dream,” he said, even if he did get suckered punched at the end of it.

“The Glass Castle” opens on Aug. 11.