Justin Bieber had finished school for the day, but the threat of detention was still looming.

Backstage at "The Tonight Show," the teen pop star's personal tutor, Jenny, couldn't find her cell phone. She suspected her pupil might have hidden it as a prank.

"Justin, did you take my phone?" she said, searching under a couch cushion. "Because if you don't have it, I'm going to have to cancel my plan right now."

"No! I swear, I didn't take it," he said, offering up a convincing puppy dog look and shaking his wispy trademark bangs out of his eyes and walking away. The teacher still seemed skeptical.

"I don't know. It's April Fools' Day," she sighed, "and he's a 16-year-old boy."

Amid the circus surrounding America's latest teen sensation, it's easy to forget that Bieber is still a Doritos-munching kid. One who is only a couple of inches over 5 feet tall; whose voice is still changing; who likes to push the boundaries of his new world.

In the last month, Bieber has performed on "The Late Show With David Letterman," twice on "The View," Nickelodeon's Kids' Choice Awards show, and "American Idol."

He played at the White House's Easter Egg Roll, where First Lady Michelle Obama enthusiastically danced along to his songs. His second album, "My World 2.0.," was released in March and debuted at No. 1 on the Billboard 200 albums chart. And last week, he was the musical guest on "Saturday Night Live," a gig that many big-name performers twice his age can't land.

As the music industry continues to struggle, Bieber, in the span of less than a year, is suddenly one of its most valuable assets, the evidence being the team of adults on his payroll that follows him nearly everywhere he goes.

There's no escaping Bieber Fever. That was apparent when Bieber recently was shuttled from a morning appearance at Radio Disney to an afternoon taping of "The Tonight Show With Jay Leno."

A clutch of young girls was waiting outside the Burbank radio station at 9 a.m. when Bieber arrived, escorted by his bodyguard, publicist, vocal coach, road manager-stylist and a representative from his music label. His manager, mother and tutor Jenny (who asked that her last name not be used to help her avoid female teen hangers-on) would join the entourage later in the day.

Many of his fans became acquainted with the singer through his YouTube videos, which he began posting online at age 13.

Scooter Braun, a 28-year-old Atlanta-based manager who had worked with rapper Asher Roth, stumbled across one such video and tracked Bieber down, persuading him and his mother, Patti Mallette, to fly to Atlanta — their first airplane flight — for a meeting. That was where Bieber famously ran into Usher Raymond in a parking lot — an occurrence that led the R&B star to go to bat for the then-unknown, helping him land a professional deal and forming a joint-venture label with Braun and Antonio "L.A." Reid, the chairman of Island Def Jam Music Group.

The rest is history.