Sara Foster: Cast on 90210 Matt Richenthal at February 26, 2009 11:25 am. Comments As previously reported, 90210 has been seeking an actress to fill the role of Naomi's older sister, Jen.Well, mission accomplished!Sara Foster has been cast in the role. According to Entertainment Weekly, she'll debut in April - and make a beeline for Mr. Matthews. Edit Delete Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.