Sara Foster has been cast in a recurring role on "90210." She'll play the sister to AnnaLynne McCord's character who arrives in town to stir up trouble. Her credits include "The Big Bounce" and "D.E.B.S."

http://www.variety.com/article/VR1118001119.html?categoryid=14&cs=1

More characters to stir up trouble? Whatever works I guess.