Michelle Trachtenberg, a former child star who appeared in the 1996 “Harriet the Spy” hit movie and went on to co-star in two buzzy millennial-era TV shows — “Buffy the Vampire Slayer” and “Gossip Girl” — has died.

Cast members of "Buffy the Vampire Slayer," "Gossip Girl" and more are remembering their co-star Michelle Trachtenberg​ after the news of her death.

The veteran actress, born in New York and raised in Brooklyn before moving to L.A., moved seamlessly from the big and small screens throughout her decades long career.