police sources told ABC News. It was further reported the actress recently underwent a liver transplant and 'may have been experiencing complications.' She is believed to have died of natural causes and police are not treating the death as suspicious, sources added to the New York Post.

Trachtenberg was best known for her work as Buffy's (Sarah Michelle Gellar) younger sister Dawn Summers in Buffy the Vampire Slayer from 2000-2003.  She also had a recurring role as 'The Witch of the Upper East Side' Georgina Sparks in Gossip Girl alongside Blake Lively spanning 2008-2012.