Michelle Trachtenberg, a 2000s mainstay with memorable roles in " Gossip Girl ," "Harriet the Spy" and " Buffy the Vampire ...

Michelle Trachtenberg, who starred in 'Harriet the Spy,' 'Buffy the Vampire Slayer' and 'Gossip Girl,' died Wednesday at 39.

Michelle Trachtenberg, the actor best known for "Gossip Girl," "Ice Princess" and "Buffy the Vampire Slayer," died at age 39.