Sarah Michelle Gellar has paid tribute to her former co-star Michelle Trachtenberg.
The actress has broken her silence following the shocking death of her Buffy the Vampire Slayer co-star on Wednesday.
"Michelle, listen to me," Gellar wrote in the post on Thursday. "Listen. I love you. I will always love you. The hardest thing in this world, is to live in it. I will be brave. I will live... for you."
The actress' character Buffy Summers said the same words to her younger sister Dawn Summers, played by Trachtenberg, in a 2001 episode of the hit drama series.
The post also included a touching image from the supernatural series, showing an emotional Trachtenberg resting her head on Gellar's shoulder.
Trachtenberg was found dead in her New York City apartment on Wednesday morning, police confirmed later that day. She was 39.
The Gossip Girl actress' cause of death has not been revealed, but she reportedly underwent a liver transplant last year and her death is not being investigated as suspicious.
Trachtenberg's Buffy co-stars David Boreanaz and James Marsters also took to Instagram to react to the sad news.
Boreanaz wrote on his Stories, "So very sad...horrible news. RIP and prayers to her and her family."
Meanwhile, Marsters wrote alongside a photo of him and the actress, "My heart is heavy today. We have lost a beautiful soul. Michelle was fiercely intelligent, howlingly funny, and a very talented person."
"She died much too young, and leaves behind scores of people who knew and loved her," the actor continued. "My heart goes out to her family who are good people, and are suffering the greatest loss anyone could bear."