A native Minnesotan, Sofia Vassilieva is an accomplshed child actress who has successfully steered her career into young adulthood. The daughter of scientists who emigrated from Russia, Vassilieva began modeling around age seven and started acting soon thereafter, most notably starring in two made-for-TV movies based on the popular "Eloise"series of children's books-"Eloise at the Plaza" and "Eloise at Christmastime." In 2004, she signed on to play Ariel DuBois, the daughter of the psychic mom played by Patricia Arquette on "Medium," and Vassilieva starred in more than 125 episodes, with her character increasingly important to the popular program's storylines. While on a break from filming "Medium," Vassilieva portrayed a terminally ill girl in the feature drama "My Sister's Keeper," going to the lengths of shaving off her hair and eyebrows to play the leukemia-stricken teen. Enrolling at Columbia University, Vassilieva continued to star on "Medium" well into the supernatural show's long run.