Michelle Trachtenberg, born on Oct. 11, 1985, was a Manhattan-born actress who started her career on Nickelodeon at only three years old. Trachtenberg went on to make a name for herself in movies

Michelle Trachtenberg, the actor known for “Gossip Girl,” “Buffy the Vampire Slayer” and “Harriet the Spy” died Wednesday. She was 39.

Sarah Michelle Gellar, Taylor Momsen and Blake Lively are among those paying tribute to Michelle Trachtenberg, who died Wednesday.

Actress Michelle Trachtenberg poses for a portrait Jan. 19, 2009, during the Sundance Film Festival in Park City, Utah.

Actress Michelle Trachtenberg, known for her roles in "Harriet the Spy" and "Gossip Girl," has died. She was 39.

(NEXSTAR) – Actress Michelle Trachtenberg has died, police sources confirmed to the New York Post and ABC on Wednesday. Trachtenberg was reportedly found in a New York apartment. The death is not currently being investigated as suspicious, the Post reported.

Actress Michelle Trachtenberg poses for a portrait at the Gibson Guitar Lounge during the Sundance Film Festival in Park City, Utah, on Monday, Jan. 19, 2009. AP Photo/Mark Mainz The sources told ...

Michelle Trachtenberg poses for a portrait during the Sundance Film Festival in Park City, Utah, on Jan. 19, 2009. Trachtenberg, the actor known for “Gossip Girl,” “Buffy the Vampire Slayer ...

on Jan. 9, 2016. (Photo by Rich Fury/Invision/AP, File) FILE - Actress Michelle Trachtenberg poses for a portrait during the Sundance Film Festival in Park City, Utah, on Jan. 19, 2009.