WASHINGTON — Michelle Trachtenberg, best known for her roles in “Gossip Girl,” “Buffy the Vampire Slayer,” and “Harriet the Spy,” has died. She was 39.

Police responded to a 911 call shortly after 8 a.m. at luxury residential tower in midtown where “officers observed a 39-year-old female unconscious and unresponsive,” according to an NYPD statement. Paramedics pronounced her dead at the scene. No foul play was suspected and the New York Medical Examiner is investigating the cause of death, police said.

The New York Post was first to report the news. 

Her death comes a year after she addressed online concerns about her health, saying she was “happy and healthy.” 

Representatives for Trachtenberg did not immediately respond to a request for comment.

Trachtenberg, born on Oct. 11, 1985, began appearing in TV commercials at the age of 3 and even landed a recurring role as Lily Montgomery on the soap drama “All of My Children.”

She starred in several children’s shows and movies including “Harriet the Spy” and “Inspector Gadget,” before landing a breakout role as Dawn in “Buffy the Vampire Slayer,” alongside Sarah Michelle Gellar.  

Trachtenberg thanked Gellar for speaking out against Joss Whedon in 2021, following abuse allegations made against the “Buffy” showrunner. “I am brave enough now as a 35-year-old woman to repost this,” she wrote on social media, and alluded to “his not appropriate behavior” she experienced as a teenage actor.

In 2001, she received a Daytime Emmy nomination for hosting Discovery’s “Truth or Scare.” Trachtenberg went on to recurring roles on “Six Feet Under,” “Weeds” and “Gossip Girl,” where she played the gang’s scheming nemesis, Georgina Sparks.

Trachtenberg’s last credited role was in MAX’s “Gossip Girl” reboot, where she reprised her role as Georgina Sparks. 

He other credits included “Ice Princess” in 2005 — playing a math prodigy and aspiring figure skater — and the 2004 teen sex comedy “EuroTrip.” For “Killing Kennedy,” the 2013 film in which she played the wife of Lee Harvey Oswald, around 80% of Trachtenberg’s dialogue was in Russian. She had learned the language from her mother growing up.