A dilemma arose on the set of “Zaide.” Hyunah Yu, the opera’s star, was portraying a Bronx sweatshop worker in a modern day interpretation of the Mozart opera. But Yu insisted on wearing her late husband’s wedding ring during performances. Yeong-Ho Yu had been shot by carjackers in 1993, just two years into the couple’s marriage.

“I was like, I don’t want to take this off. I’ve always worn it,” Yu recalls.

As the crew fretted, the costume designer came up with a suggestion: Could Yu wear a Band-Aid over her ring?

“So I was able to keep my ring on,” Yu says with a laugh. “We had a Band-Aid over it the whole time.”

“For me, it’s a comfort,” explains the widow. “Because it’s a piece of [my husband]. Because he never took it off.”

For the 39-year-old soprano, her husband’s death and her musical career are inextricably linked. Had she not lost him 14 years ago, she may never have immersed herself in the world of music as an outlet for her grief and enjoyed the career she has today. Music, she believes, was a gift from God and her key to healing.

“No one is exempt from pain,” she says. “When the music is interpreted, I think all the pain that I’ve had and all that I went through, it’s all in there. People feel it. And it’s a gift.

“I’ve been given (the gift of) music, and I want to share it.”

And Yu has indeed shared it with audiences around the world. A petite woman with expressive eyes and a strong square jaw, the vocalist has quickly ascended in the world of classical music. Last year she won the title role of “Zaide,” directed by Peter Sellars, which played in London, Vienna and New York. In January, EMI released her first self-titled solo album featuring Mozart and Bach arias. Critics have lauded her emotional depth and vocal range.

“Her voice is not a huge one,” says Jim Lowe, an arts editor at the Times Argus in Montpelier, Vt. “But it’s special. It has what I would call a ruby-like quality. It’s very personal and it touches people very personally. But it’s also her passion for the music that comes across. She doesn’t sing the music — she lives it.”

Hyunah Kim with 4-year-old Daniel in Princeton, N.J.

At age 13, Yu, born in South Korea, immigrated with her family to the United States. Her father, a Presbyterian minister, filled their Texas home with the sounds of Handel and Schubert throughout her and her four siblings’ childhood. The second oldest, Yu grew up singing and playing cello, but viewed music as just a hobby. Her parents had hoped she would pursue a career in classical music as her older sister had, but instead, she gravitated toward medicine, convinced that God wanted her to be his healing hands. She earned a bachelor’s degree in molecular biology from the University of Texas in Austin and planned to be a doctor.