"I don't even have time for boys!" says Rihanna, the seventeen-year-old Jay-Z protegee whose dancehall-tinged single "Pon De Replay" is lighting up both dance floors and pop radio. The Barbados native is currently preparing for full-fledged stardom while finishing high school, spending eight hours a day with a choreographer and fifteen hours a week with a tutor amid a globe-trotting performance schedule. Thankfully, Rihanna (full name: Robyn Rihanna Fenty) has the goods to back up the expectations: Her debut album, Music of the Sun (out August 30th), is a seductive mix of big-voiced R&B and souped-up island riddims -- what Beyonce might have sounded like if she had grown up in the West Indies and skipped the whole Destiny's Child thing.

"I signed her in one day," says Jay-Z. "It took me two minutes to see she was a star." After the rapper turned Def Jam president got ahold of her demo, he invited Rihanna to his office for an impromptu showcase that included an a cappella rendition of Whitney Houston's "For the Love of You." "I was in the lobby just shaking," Rihanna says. "But after the performance Jay said, 'We're interested.' By 3 a.m. the lawyers had banged out the contract."

Before she was discovered by a vacationing American producer in December 2003, Rihanna was just another beach-dwelling island girl, skipping school and absorbing a mix of calypso, reggae and American hip-hop at the clubs in her hometown of St. Michaels. Though she had won a high school talent contest with a performance of Mariah Carey's "Hero," her vocal training was limited to singing in her bedroom. "I would hold a broom like a mike stand," she says. "My neighbors would complain -- they always knew when I was home."

Having left her family and friends in Barbados for suburban Connecticut and not old enough to get into most American clubs, Rihanna is impressively focused -- she's taken to her studies, diving headlong into American history and recently devouring The Adventures of Huckleberry Finn. But she was more than a little giddy when she encountered her idol. "I met Beyonce!" she exclaims. "We hung out at [Jay-Z's] 40/40 club. She wrote me a note that said, 'When you get onstage, just let loose. Have fun. You're in control.'"