Henry, 12, who plays the Englishman as a boy, told the Almanac in a telephone interview that he has seven minutes on stage, starting with a solo dialog that evolves into a solo song and then a duet with acclaimed baritone Thomas Hampson, who sings the role of the hero as an adult.
Henry said he hangs out in the backstage canteen when not performing, and is considering a career as a professional singer.
"I love singing," he said when asked how he came to the art. "I love music. I don't know. It's kind of like a break from life. It gets me out of my routines. It's just a wonderful thing."
Henry's mother, Kristina Phipps, asked him at around age 6 or 7 if he wanted to join a chorus; he agreed to try it, and joined the Ragazzi Boys Chorus. The chorus helped Henry prepare for the "Heart of a Soldier" auditions. "I owe a lot to them," he said.
He and his understudy, or cover, are the only kids in the cast, he said. After his first audition, he was called back for a second, and got the part about two hours after that. The cast rehearsed for about four weeks over the summer, often every day, he said.
The opera, with music by Christopher Theofanidis and based on a book by New York-based journalist James B. Stewart, runs for seven performances in September, the next being Wednesday, Sept. 21.
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Henry's interest in opera is about as old as his involvement with this production. "I really didn't know a thing about it until I got this part," he said. "Now that I'm in it, I've got the bug, and I'm thinking of trying out for another opera."
He does get butterflies, but they go away. "Once I'm on and I start singing, it comes back and I do what I've always done and it kind of works," he said. "I wouldn't be surprised if I grow up to be a professional singer."