Katie Cassidy has been added to Supernatural cast.
From Reuters.com:
Vandervoort, Cassidy in CW dramas
By Nellie Andreeva
LOS ANGELES (Hollywood Reporter) – Canadian actress Laura Vandervoort has landed the coveted role of Kara/Supergirl on the CW's "Smallville," and Katie Cassidy has been added to "Smallville's" companion series, "Supernatural."
Kara/Supergirl will have a major presence on "Smallville" in the coming season. The character will be introduced in the show's seventh-season premiere.
Cassidy's character, Ruby, will make her first appearance on "Supernatural's" third-season premiere. Ruby is a fellow demon hunter who Sam and Dean Winchester (Jared Padalecki, Jensen Ackles) meet when they begin searching for the masses of demons who escaped from hell in the Season 2 finale.
Cassidy, daughter of '70s pop star David Cassidy, has appeared in such features as "Click," "When a Stranger Calls" and "Black Christmas." She also has been signed to play Lucy Ewing in the upcoming big-screen adaptation of the TV series "Dallas." On TV, she had a recurring role on "7th Heaven."
Reuters/Hollywood Reporter