MINNEAPOLIS — When Barkhad Abdi and three other amateur Somali actors from Minnesota learned they had won major roles in a new Tom Hanks movie, they tore off their clothes and jumped into the Pacific Ocean.

“It was exciting,” Abdi recalls of that day on the beach in Santa Monica, Calif. “We had to make sure that wasn’t a dream.”

Abdi and his fellow actors from Minneapolis are now living that dream of red carpet premieres and Hollywood endings. The four portray Somali pirates who hijacked an American cargo ship off the Horn of Africa in 2009 and took its captain, played by Hanks, hostage in “Captain Phillips,” opening tonight. The ordeal ended when U.S. Navy sharpshooters picked off three of the pirates holding Capt. Richard Phillips captive in a lifeboat.

Abdi, 28, makes his acting debut in “Captain Phillips” as Muse, the pirates’ skinny ringleader, and is generating supporting actor Oscar buzz for his performance. Before that, he had shot and edited videos but “nothing major,” he said. Now he wants to make acting his career.

“It feels great, and a little bit scary,” Abdi said of his new fame. “I was just kind of a private person (before the movie). This took part of my life.”

Abdi and the other three Somali actors — Faysal Ahmed (the “muscle” of the pirates), Barkhad Abdirahman (the youngest pirate, nicknamed “Little B” by his castmates) and Mahat M. Ali (the lifeboat’s navigator) — all answered an open casting call at the Brian Coyle Community Center, a hub of Minneapolis’ large Somali population — in November 2011. Generic flyers sought actors for what was described only as a new Tom Hanks movie. Over 700 aspiring actors showed up, filling the center.

“There were so many people I just had to put every single person on tape,” casting search director Debbie DeLisi said. Afterward she went to a friend’s house where they watched every clip and voted yes, no or maybe. The video also was uploaded for the film’s main casting director in Los Angeles.

DeLisi said she chose Minneapolis because the city has the largest population of Somalis in the U.S. (The U.S. Census says roughly 25,000 Somalis live in Minnesota, while local advocates peg the number as high as 100,000). Another casting call was held in Columbus, Ohio, also home to a growing Somali population, and submissions were accepted from England and Somalia.

In the end, the field was narrowed to the four Minneapolis actors, who all knew each other.

“I would say they were anointed,” DeLisi said. After they were cast, DeLisi’s assistant took the actors shopping for swim trunks at the Mall of America and made sure they had passports for Malta, where most of “Captain Phillips” was shot.

DeLisi said she was looking for “heart and grit” in the actors playing the pirates.

“It’s not about jumping and being the bad guy,” she said.

To capture the shock of the ragtag band of armed pirates storming the ship Maersk Alabama, British director Paul Greengrass (“The Bourne Ultimatum,” ”Flight 93) kept the Somali actors apart from Hanks until their first confrontation on the bridge.

“It’s never an easy thing to scare someone you know and admire,” Abdi said of facing off against Hanks. “For me, it was really a nerve-racking scene and I understood the weight of it.”

Abdi and Ahmed recall Hanks as humble and always joking, and say the two-time Academy Award winner, for “Philadelphia” and “Forrest Gump,” was their mentor.

In their first fight scene aboard the narrow lifeboat, the 6-foot-3 Ahmed says he accidentally grazed Hanks with his fist. Hanks shrugged it off, the two talked and a second fight scene filmed a couple days later went perfectly, Ahmed said.

“He was a really tough guy,” Ahmed said.

Ahmed, 29, was born and raised in Yemen and came to the U.S. in 1999 at 14. He said the main motive for the pirates from war-torn Somalia was to get money. He tried to imagine himself that desperate.

“If you were put into that situation and only wanted to change your life, what would you do? For me, that’s something I constantly thought about,” Ahmed said.

Abdi was born in Mogadishu, Somalia, and raised in Yemen. He came to the U.S. in 1999 when he was 14 with his parents and siblings, and said he also understands the pirates’ motivations.

“What they’re doing is bad. I totally agree with that,” Abdi said. “I was fortunate to have parents who got me out … So they were stuck in this situation. And I feel compassion.”