The network confirmed to Access Hollywood on Wednesday that the singer-actress is joining the show's cast for its upcoming third season. She's set to debut in the fourth episode on October 5.
According to Entertainment Weekly, who was first to report the casting, Hilary will play Olivia Burke, a movie star who retreats from the limelight for a "traditional college experience" at NYU, where she'll room with Vanessa (Jessica Szohr).
That may not be the third season's only odd college pairing – the second season concluded with Georgina Sparks (Michelle Trachtenberg) requesting to room with frenemy Blair Waldorf (Leighton Meester) at the New York school.
Hilary had an opening in her schedule after NBC turned down her pilot, "Barely Legal."
"Gossip Girl" returns to The CW this September.
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