Samantha O’Brochta, of Freeland, thought she was dreaming when the Seattle Opera called her back.

“A friend of mine posted the audition on Facebook,” O’Brochta said.

That’s how she found out the major company was holding auditions for the chorus of “Porgy and Bess,” George and Ira Gershwin’s famous portrait of life and love on the fictitious Catfish Row in 1920s South Carolina.

“I thought, even if I didn’t get it, I still wanted to try out,” O’Brochta said.

After the November audition, the young singer was called back a month later. When she was cast, she was flabbergasted because her forte is musical theater, and she is not much of an opera singer, she said.

“I didn’t believe it at first,” she said, “because I hadn’t heard anything for about three months. But then they sent me the music and I guessed it wasn’t a dream then.”

In June, about a week after finishing the semester at Western Washington University in Bellingham, where she is a junior journalism and theater student, O’Brochta threw herself headlong into the Seattle rehearsals.

The chorus rehearsed every week night for six weeks at the opera’s rehearsal studio on Terry Avenue under the guidance of chorusmaster Beth Kirchhoff and musical conductor John Demain, with stage direction by Chris Alexander.

The people working at the opera were not what O’Brochta expected.

“You expect everyone at the opera to be snobby. Beth is super sweet and has been great to work with and it’s been easy to learn from her,” O’Brochta said of the chorusmaster.

“The music took three weeks to learn and then we started the staging,” the young actress said.

They were on the McCaw Hall stage where all Seattle Opera performances take place in the Seattle Center for about 10 days before opening Saturday, July 30. Performances run through Saturday, Aug. 20.

There were more than a few lessons learned from the experience, O’Brochta said.

“I discovered that opera and musical theater are so completely different. Opera is all about the singing. We were told to focus on the conductor above all else,” she said, “and the acting is not as important.”

O’Brochta shares the stage with about 30 other chorus members. At 20, she is the one of the youngest in the group and it is the first time she is being paid for her theatrical work.

“The music is gorgeous. The principals are amazing. Especially Gordon (Hawkins, who plays Porgy) who sings ‘It Ain’t Necessarily So,’” she said.

“He adds so much. He dances around — he’s so great!”

O’Brochta said she is equally wowed by Mary Elizabeth Williams, who plays the character of Serena in the show.

“It was so amazing the first time we heard her sing ‘My Man’s Gone Now.’ We were all crying,” she said.