The move Justin Gaston suddenly pulls could easily cause a 9-year-old girl's head to explode from excitement. In the midst of talking about Scripture, he yanks up his shirt and tugs his pants down to reveal a toned left flank with a long tattoo that runs down to the top of his buttock. "It's Psalm 7:8, 'Judge me, O Lord, according to my righteousness,'" says the 20-year-old singer-songwriter-model, a kid you're reading about, let's be honest, because he's Miley Cyrus' boyfriend. As the sun sets, the rangy six-footer with bovine brown eyes capped by dogwood-thick eyebrows, gazes from a hotel suite overlooking Venice Beach. "I don't want to be judged—so I put it on my body in an attempt to become that bold."

A little courage would certainly help him bear the scrutiny that comes with being the beau of Hannah Montana, as would heavenly protection from the near-Biblical plague of overweight men wielding cameras—Gaston admits to lately having had nightmares punctuated by paparazzi flashes.

Gaston—unlike Cyrus, who was booking acting gigs at 10—has arrived in the world of celebrity with little time for preparation. After a modeling agent discovered him three years ago, the devout Christian from Pineville, Louisiana, spent three miserable months in New York before heading to L.A. to transform himself into the next John Mayer. His shaggy good looks landed him a spot on Nashville Star, on which he discovered an ally in host Billy Ray Cyrus—himself a churchgoer with former pro-ball aspirations—who summoned Gaston for frequent powwows in his tour bus. When Gaston was booted after only three episodes, Cyrus' on-air farewell was lavish. "This guy's gonna be a big, big movie star," he said. "I'm calling it right now! Tom Cruise, look out!"

"I kinda saw it coming just with the way Billy Ray was with him," says Ruby Cantu, a Nashville Star producer who lived with the contestants. Soon, Billy Ray ushered Gaston onto the Hannah Montana set. "It's like if you had a 16-year-old daughter who said, 'Oh, Daddy, he's so cute—I want to meet him,'" Cantu says. "That's exactly what happened."

Cantu says it's real affection: "puppy love . . . holding hands and being cute with each other." Others wonder. "It seems like a de facto advertisement," says Courtney Hazlett, MSNBC's pop-culture columnist of the YouTube video of Cyrus dancing and swooning while Gaston sings. Is Gaston a girl's first love or part of a stage dad's cynical ploy to help his multi-million-dollar daughter forge a post-Disney career?

In contrast to Cyrus' ex, Nick Jonas, Gaston hasn't spent his life hermetically sealed in a Magic Kingdom turret; take, for instance, the photo shoot Gaston did for the online underwear retailer International Jock, the mention of which makes him cringe. "It's not something my mom would be proud of," he says. He scoffs at the Internet chatter suggesting he's been living in the Cyrus home—"No! I live in an apartment in North Hollywood with two guys!"—and seems at a loss when asked basic questions about his girlfriend. He won't identify the person who repeatedly calls his iPhone during the interview. Finally he hurries off to take the call behind closed doors.