The Gossip Girl family is mourning Michelle Trachtenberg. Chace Crawford, who played Nate Archibald on the CW show, posted a tribute to the late actress, who was found dead in her apartment Wednesday morning.

News of Michelle Trachtenberg's death prompted tributes from her friends and former "Buffy," "Harriet the Spy," and "Gossip Girl" costars.

Michelle Trachtenberg was found in her New York City apartment, and the death is not believed to be suspicious, police said.