THE OLSENS': THE FAMOUS TWIN SINGING SENSATION

Singing Sensations

The 6-year-old twins record their first album, Brother for Sale, the release of which launches the Olsen phenomenon. ''I like the song called 'I Want to Trade My Brother,''' Mary-Kate tells PEOPLE. ''Yeah,'' Ashley agrees with a giggle. ''When we were rehearsing it, our brother Trent said, 'I hate that song!'''

ASHLEY AND MARY KATE OLSEN

Ashley and Mary-Kate Olsen\ are known for their individual style, but the twins were first famous as Michelle Tanner on Full House. Before turning 10, they had already earned millions, and at 18, took charge of their billion-dollar brand, Dualstar.

While Mary-Kate struggled with anorexia and took a leave of absence from college in 2005, Ashley continued her studies at New York University. Today, her influence as a fashion trendsetter garnered her spreads in Harper's Bazaar, Vogue and Teen Vogue, and with Mary-Kate, she has launched the fashion line, The Row, and its lower-priced counterpart, Elizabeth and James.