Michelle Trachtenberg, known for roles in shows including Gossip Girl and Buffy the Vampire Slayer, has died at the age of 39, according to reports.

Her body was reportly discovered at home in New York by her mother early on February 26, and authorities are cited as saying they are not considering the death to be suspicious. She had recently undergone a liver transplant, and it’s believed by people close to the situation that complications from that surgery might be responsible; an autopsy is expected to confirm cause of death.

Trachtenberg was a longstanding presence on television for a generation, appearing on Nickelodeon’s The Adventures of Pete & Pete in 1994 at age 8; she’d go on to become known to genre fans as Buffy’s younger sister Dawn in the WB/UPN series Buffy the Vampire Slayer in the final seasons of the show. It’s arguably her most recognizable role outside of Georgina Sparks, the untrustworthy (of course) socialite and former friend of Serena van der Woodsen from the CW’s Gossip Girl, a recurring role throughout the series’ heyday. In later years, she’d be seen guesting on everything from House and Law & Order: Criminal Intent through forgotten medical drama Mercy and Showtime’s Weeds.

The actor also made numerous movies, including the 2006 remake of horror slasher Black Christmas, and Gregg Araki’s Mysterious Skin, playing the best friend of Joseph Gordon Levitt’s main character Neil. (She was also Penny in the live action Inspector Gadget movie in 1999, an iconic role for anyone in the know.)

Trachtenberg’s death comes as a shock — she was so young — and also a tragedy, as it felt as if the industry was starting to finally realize how talented she was once again after some time in the wilderness; she’d recently made an appearance in the rebooted Gossip Girl, and was at the center of 2024 movie Spiral. She is survived by her family, and will be missed by fans and friends alike.