Michelle Trachtenberg passed away at 39. Starting as a child actress, she went on to star in movies like Harriet the Spy and Ice Princess as well as series like Buffy the Vampire Slayer and Gossip Girl. 

As news of her passing made headlines, her former co-stars have taken a moment to remember and pay tribute to Michelle.  

Her Buffy the Vampire Slayer co-star Alyson Hannigan was among the first to honor Michelle's memory on social media. She captioned a series of photos with Michelle, writing, "I am deeply saddened by the news of Michelle’s passing. She brought a loving energy to the set of Buffy. My thoughts are with Michelle’s family and friends."

James Marsters, who starred as Spike in Buffy the Vampire Slayer, had a lengthy post dedicated to Michelle. He wrote, "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. My heart goes out to her family who are good people, and are suffering the greatest loss anyone could bear. I hope everyone can give them space to heal in this most difficult time. Godspeed Michelle. You are missed."

Kim Cattrall, who worked with Michelle in the 2005 movie Ice Princess, posted a photo of a scene from their movie, captioning it with: "Rest in peace sweet Michelle 💔"

Melissa Gilbert paid tribute to her A Holiday for Love co-star, who was only about 11 when they worked on the said television film, by writing, "Oh Michy…and we lived so close to one another…..my heart aches for your family and all those who loved you so… @michelletrachtenberg #ripsweetgirl"

Saturday Night Live's Kenan Thompson who also worked on several Nickelodeon projects like Michelle took to social media to honor her: "Our first Nick movie star has departed us!! She was my friend and now she rests!! 🙏🏾 Check on your people!!! ❤️"

Chace Crawford, who worked with Michelle in Gossip Girl, shared that the actress was "one of a kind." He posted three photos with Michelle, captioning them with: "I remember her coming on set for the first time and just absolutely owning it. She was a force of nature and just so so unapologetically funny and magnetic.. remembering those years with a big smile. Just a terrible loss. Love you ❤️"

Taylor Momsen, who was also part of the Gossip Girl squad, mourns the loss of her friend. In a heartwarming post, Taylor honored Michelle, writing, "In shock…When I met this girl 17 years ago I knew we’d be friends..she was smart and sassy, bold and sensitive, funny as fuck and filled with fire. She was simply awesome. I’ll miss our late night calls that no one should ever hear but us. She was always in my corner and there to support me whether I was right or wrong. I will miss you everyday my love..I think we truly understood each other and I am so grateful to have had a friend like you in my life for so long..You were a true friend to me which is a rarity in this world and I can’t believe I won’t hear your voice again..I hope you’re fucking up heaven for both of us..I love you so much Michelle, my heart is on the floor. I’m still in shock but I needed to honor her, she deserves more than this. I grieve with all her fans around the world, and my heart is with her family and loved ones. I have so much to say, but she’s the only one I’d want to say it to, my love to you all xxt"

Michelle's other Gossip Girl co-star, Ed Westwick, posted a photo of the actress on his Instagram Stories with the caption "So sad to hear the passing of @michelletrachtenberg. Sending prayers."

Lead photos from @michelletrachtenberg