Danica McKellar and her younger sister, Crystal, began acting at a young age in their mother's dance studio. In 1982, the family moved to Los Angeles and a few years later, Danica appeared in her first commercial. A few guest appearances in The Twilight Zone (1985) were followed by her breakthrough in The Wonder Years (1988). Danica has had good grades in math and French. In her spare time, she likes to go skiing, swimming and surfing.