Michelle Trachtenberg, the actress best known for her roles as Dawn Summers on Buffy the Vampire Slayer and Georgina Sparks on Gossip Girl, has died. She was 39. Trachtenberg was found unresponsive in her New York City apartment early Wednesday morning,

Trachtenberg starred as the cunning Georgina Sparks on the beloved CW series, appearing in each of the six seasons and reprising her role in the recent reboot.

Actress Michelle Trachtenberg, known for roles in “Buffy,” “Harriet the Spy,” and “Gossip Girl,” has been found dead in New York City at the age of 39, according to a police spokesperson. The NYPD responded to a 911 call around 8 a.