Michelle Trachtenberg’s former costars are paying tribute to her in the wake of her sudden passing. Trachtenberg has died at 39 years old, Deadline reported today. The New York Police Department responded to a 911 call on Wednesday morning,

Tributes have been pouring in following the sad news of Michelle Trachtenberg's death on Feb. 26 at the age of 39. Known for her roles on Gossip Girl and Buffy the Vampire Slayer, Trachtenberg was beloved by many,

The NYPD confirmed Trachtenberg was found “unconscious and unresponsive” by police and pronounced dead by EMS workers. Her death is not deemed suspicious. Trachtenberg shared a throwback photo with Instagram followers on Feb. 18. The close-up shot showed the “Gossip Girl” vet on the red carpet.

Michelle Trachtenberg's cause of death remains undetermined, but a source reveals she recently had a liver transplant.

Sarah Michelle Gellar is paying tribute to her late "Buffy the Vampire Slayer" co-star Michelle Trachtenberg after her tragic death at age 39.

Sarah Michelle Gellar has paid tribute to her former Buffy The Vampire Slayer co-star Michelle Trachtenberg following her death Wednesday at 39.

Sarah Michelle Gellar mourned the death of “Buffy the Vampire Slayer" co-star Michelle Trachtenberg in an Instagram post.