Michelle Trachtenberg from Buffy The Vampire Slayer is set to join the cast of Gossip Girl. Looks like she got Mischa Barton's leftovers. She'll play the role initially offered to Mischa of Georgina Sparks, a troublemaker from Serena's (Blake Lively) past.
This Michelle girl is really coming up the ranks. She's also starring along side Zac Efron in 17 Again, which comes out in August.