In a statement provided to Entertainment Weekly on Wednesday, O'Donnell said of Trachtenberg, "I loved her very much. She struggled the last few years. I wish I could have helped.

Michelle Trachtenberg, the actress known for 'Harriet the Spy,' as well as TV shows like 'Buffy the Vampire Slayer' and 'Gossip Girl,' has died.

Michelle Trachtenberg—the film and television actor known for roles in Buffy The Vampire Slayer, Gossip Girl, Harriet The Spy, and Ice Princess—had died. Her death was confirmed by ABC News. The outlet reports that she had undergone a liver transplant recently and is believed to have died from natural causes. She was 39.