Michelle Trachtenberg, the actress known for her roles in "Gossip Girl" and in the 1990s hit series "Buffy the Vampire Slayer," has died, according to multiple reports.

Blake Lively, Sarah Michelle Gellar and other stars remembered Trachtenberg’s work ethic and friendship in social media posts.

The "Gossip Girl" and "Harriet the Spy" alum, who rose to fame as a child star, was found dead in New York City on Wednesday, according to police.

Michelle Trachtenberg was found in her New York City apartment, and the death is not believed to be suspicious, police said.

Georgina was played by the actress Michelle Trachtenberg, who was found dead at 39 in her Manhattan apartment on Wednesday. Her performance as the teenage supervillain brought an arch flair to a character who was only a minor figure in the novels that were the basis for the show, but became a fan favorite onscreen.

Hollywood is mourning actress Michelle Trachtenberg, who died on Wednesday. She was 39. Trachtenberg, best known for roles in "Buffy the Vampire Slayer," "Gossip Girl," Disney's "Ice Princess" and more, is believed to have died of natural causes, police sources told ABC News.

Blake Lively and Alyson Hannigan are among the former "Gossip Girl" and "Buffy" actors mourning the death of their one-time co-star, Michelle Trachtenberg.

Justin Timberlake's latest concert left many fans disappointed, as the pop star leaned heavily on new material.

Michelle Trachtenberg, an actress best known for her roles in "Buffy the Vampire Slayer" and "Gossip Girl," has died at age 39.