Soon, Serena van der Woodsen (Blake Lively) and Blair Waldorf (Leighton Meester) will land two new recruits ... Singer Hilary Duff, 21 years, ex-girlfriend of Joel Madden before it s'�prenne of Nicole Richie has confirmed its presence in the cast of the adventures of the golden youth estudiantine New York. Hilary Duff, back from his vacation on the Hawaiian beaches, will perform Olivia Burke, a