Michelle Trachtenberg, the actress who rose to fame as a child star with films like “Harriet the Spy” and went on to have memorable roles on TV shows including “Gossip Girl,” has died, according to an NYPD source.

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

The actress was found dead in her New York City apartment on Feb. 26. Her former co-stars, including Sarah Michelle Gellar and Blake Lively, are honoring her memory on social media.