Imagine growing up with one family, never knowing you had another sibling, or even more brothers and sisters, in the world. Alex Kurtzman, who has written movies such as 2009’s “Star Trek” and 2007’s “Transformers,” wrote and served as executive producer for “People Like Us,” a film loosely based on this experience in his life.

Kurtzman grew up knowing his father had two other children, but their paths didn’t cross until years later when he was 30 years old and met his half-sister at a party. He was already mulling an idea for a script but was inspired after this encounter. It took eight years to complete it.

“I couldn’t put it out into the world until I felt like it was ready to go,” he said. He wrote the film with producer Roberto Orci and their mutual friend Jody Lambert.

“We were writing for ourselves. It was a very cathartic process,” Kurtzman said. “It was wrong a lot longer than it was right. We had to separate truth and fiction in terms of my own life.”

Chris Pine plays the lead, Sam, a salesman who lands a huge deal, then learns his father died — all on the same day. He flies to California for the funeral, but soon learns of a sister he never knew he had named Frankie, played by Elizabeth Banks.

Pine, who is known for roles in “Star Trek” and “Unstoppable,” said the character immediately drew him in. He said, “I understood (Sam) even though I felt the audience would hate him. He’s a conflicted character.”

The script also resonated with the actor. Pine said, “It’s very rare that you read a script from front to back that you don’t put down. That’s a great feeling. It’s a meaningful thing.”

He also said the film is a reflection of family — flaws and all.

“These are things all of us deal with when we become adults. Our parents and sisters and brothers are not superhuman. They are real, screwed up, faulted people,” he said. “The only thing you have a choice over is if you choose to accept them and love them, or push them out of your life and resent them.”

Michelle Pfeiffer plays Lillian, Sam’s mother. Pine enjoyed working with her, although he couldn’t quite get one of her characters out of his head.

“I thought about the scene in ‘Scarface’ when she walked down the staircase in the silk dress,” he quipped. Pfeiffer played Elvira Hancock in the Brian De Palma gangster classic with Al Pacino as Tony Montana.

Portraying a torrid relationship between mother and son on screen was challenging. He said, “The relationship is quite fractured.”

Speaking of family, Kurtzman said he was slightly fearful about his family’s reaction to the movie but was comforted by their constant support.

“I wanted to be utterly respectful,” he said. “I think everybody felt proud that I was going down this road. It was a huge responsibility that I was honoring them in the right way and that I was doing right by them.”

Kurtzman met someone at the Atlantic Station screening on June 7 at who shared his experience.

“A woman grabbed my arm and said, ‘I just want you to know I just found out that I had a brother I never knew about. I didn’t want to meet him until I saw your movie,’” he said. “It was pretty amazing. It’s gratifying.”