And Smallville's Supergirl is...
Vandervoort fits the description from the Supergirl casting call: Caucasian 19-year-old who must be blond, smart, beautiful and funny. However, she is 22-years-old but since Tom Welling is a 30-year-old playing a teen, I guess fans will allow the actress to be three years older than the character!
Laura Vandervoort is better known for her portrayal of Sadie in Canada's Instant Star. She also guest starred on various TV shows such as CSI, The Dresden Files, Doc, and Mutant X.
Smallville fans should expect a handful from Kara. Series creator Al Gough reveals that he wanted a character who would shake things up. "She may be Clark Kent's cousin, but that doesn't mean she's going to be the obedient one!" he added in an interview with People. The character is also said to possess all of Clark's powers, including some he yet has to develop (read here that she can fly). Her rebellious demeanor will put her at odds with Clark but will intrigue Lex. She will potentially be a love interest for Jimmy Olsen. Kara is set to make her first appearance in the Season 7 premiere which should air sometime mid-September.