Over the past month, Trachtenberg has posted a few photos on Instagram, including a few throwbacks. Her most recent selfie appears to have been uploaded on Wednesday, February 12.

Michelle Trachtenberg underwent a liver transplant shortly before her death at age 39, a source told NBC New York. It’s not known if the “Gossip Girl” actor suffered complications from the transplant. At this time, no cause of death has been determined, according to the New York City chief medical examiner’s office.