Former child star and beloved millennial actor Michelle Trachtenberg, best known for her work on "Buffy the Vampire Slayer" and "Gossip Girl," was found dead at her New York City home, police said Wednesday.

Ed Westwick is mourning the death of his Gossip Girl costar Michelle Trachtenberg. Westwick, who played the sleazy Chuck Bass on the CW show for six seasons, shared his condolences for the late actress,

Comedian and former Nickelodeon child star Kenan Thompson shared a video on Instagram of the two of them on Nick, writing: “Our first Nick movie star has departed us!! She was my friend and now she rests!!” One of Trachtenberg’s first roles was in the Nick series “The Adventures of Pete & Pete.”