In only 15 months, pop sensation Lady Gaga has become the hottest performer in music right now. She's sold 8 million records, earned six Grammy nominations and became the first artist in history to have four number one hits on a debut album. But before the costumes and chart-toppers, there was New Yorker Stefanie Joanna Angelina Germanotta.

Stefanie studied classical piano beginning when she was just 4 years old. By the time she reached high school, she was writing her own songs and eventually started performing in local night clubs. Only a few years later, she said goodbye to Stefanie and Lady Gaga was born.

These days, Lady Gaga says she prefers to be addressed as just Gaga. "It feels weird when people call me Lady," she says. "It's so formal."