Bobby Hill, the boy soprano who charmed the nation

Bobby Hill has a singular excuse for missing a few classes at Central High School. The 14-year-old boy soprano from the Andorra section of Northwest Philadelphia became an overnight sensation when he sang for Pope Francis at Saturday night's Festival of Families.

He and his father, Jerrold, spent Monday in New York City making the rounds of talk shows, speaking with agents, and navigating the crowds of people who recognized him from the televised concert or what has come after. Wednesday may be more of the same. "Everyone is calling," said Stephen Fisher, artistic director of the Keystone State Boychoir.

Hill joined the group seven years ago. "Music is an escape," he said Tuesday. "Things are more free and relaxing. It connects me with my spiritual side." Classical is his favorite genre, Bach the first composer he names.

Fisher had been warned that a dead spot in Saturday's concert was likely during a set change. A minute isn't long offstage; onstage, it's an eternity. Could Fisher get his choir to do something?

"I'll do better than that," he said. "I'll give you a choir of one."

Backstage, Hill tried out on Andrea Bocelli the "Pie Jesu" from Andrew Lloyd Webber's Requiem. "Bravo! Bravo! Bellissima!" was the famed tenor's reaction.

Then, on five minutes' notice, the boy took the stage without even piano accompaniment, handling the microphone like a seasoned pro.

"When I went out on the stage, I thought, 'There's no turning back now.' " The captivated pope gave Hill, who comes from a churchgoing family, a rosary.

"I could never have done that," said the Oscar-winning actress Charlize Theron when she ran into Hill on Monday during his talk-show rounds. "Kudos to you!"

Nonetheless, his Facebook page no longer accepts comments. The male treble voice is still misunderstood in many quarters of society, and some trollish remarks have come his way. He has heard them before: "I'm able to tune them out."

Or sing them away. The power in his voice emerged four years ago. "It felt weird to sing those high notes - and fill a church," he recalled.

If he's not at the Keystone State Boychoir's joint concerts with Solvguttene Boys of Silver at 7:30 p.m. on Thursday in Abington Presbyterian Church or with the Bucks County Choral Society on Oct. 25 at Our Lady of Guadalupe Church in Doylestown, it probably will be because he's still swept up in (or, more likely, exhausted by) his wave of fame.

Of course, there's also the possibility, at his age, of an abrupt voice change. "One never knows how long Mother Nature will cooperate," Fisher says.

Hill knows he may be singing on borrowed time. But Fisher, who has worked extensively with young voices, says boy sopranos often continue employing falsetto after their voices change. The trick is finding the smooth bridge between that and the rest of the voice - it's called passaggio - plus resisting the temptation to do more masculine belting.

For now, though, a bigger worry might be the impact of sudden fame. But the fact that Hill now says he wants to sing for President Obama doesn't mean it's all going to his head.

"Any bravado he has, he had it before. That's what allowed him to walk out there onstage without blinking," said Fisher. "He's going to be OK."

dstearns@phillynews.com