Sarah Michelle Gellar and Other Co-Stars Remember Michelle Trachtenberg: ‘I Will Live for You'

Tributes are pouring in for Michelle Trachtenberg.

The actress, who gained notoriety with TV and film roles such as Harriet the Spy and Buffy the Vampire Slayer, was found dead in her New York City apartment, police said on Wednesday. She was 39.

Trachetenberg’s former co-stars posted tributes to the actress on social media.

Sarah Michelle Gellar, 47, paid tribute with a heartfelt Instagram post featuring photos from their time on Buffy the Vampire Slayer, along with the caption, “Michelle, listen to me. 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.”

As noted by People, Trachtenberg joined Buffy for its fifth season as Dawn Summers, Buffy’s mystical “key” sister, and remained with the show until its series finale in 2003.

Melissa Joan Hart shared her heartbreak over Trachtenberg’s death on Instagram along with a clip from Clarissa Explains it All.

“I'm heartbroken to hear of the passing of @michelletrachtenberg!! So young, so talented and so sweet!” wrote Hart, 48. “I think this was about 1992 and the episode was an idea I had about babysitting a total nightmare. But Michelle was nothing like her character and even this young, we got along wonderfully.”

Blake Lively shared an emotional Instagram Story on Wednesday recalling the first day she met Trachtenberg, describing her as “electricity,” and as someone whose presence instantly changed the vibration of a room.

“Everything she did, she did 200%,” wrote Lively, 37. “She laughed the fullest at someone's joke, she faced authority head on when she felt something was wrong, she cared deeply about her work, she was proud to be a part of this community and industry as painful as it could be sometimes, she was fiercely loyal to her friends and brave for those she loved, she was big and bold and distinctly herself.

“Hold those you love and have loved dear," she continued. "The world lost a deeply sensitive and good person in Michelle. May her work and her huge heart be remembered by those who were lucky enough to experience her fire.”

Chase Crawford, 39, who worked with Trachtenberg on Gossip Girl, shared a carousel of photos on Instagram, writing, “Michelle was one of a kind. 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.”

Kim Cattrall, who starred alongside Trachtenberg in Disney’s Ice Princess in 2005, wrote on X, “This is Heartbreaking. So talented, much too young. RIP Sweet Beauty. xo.”

Rosie O'Donnell, who worked with Trachtenberg on Nickelodeon’s Harriet the Spy, sent a statement to Us Weekly, calling her death “heartbreaking.”

“I loved her very much,” O’Donell, 62, told the magazine. “She struggled the last few years. I wish I could have helped.”

According to an ABC report, Trachtenberg was found in her apartment by her mother. Sources told the outlet she had recently undergone a liver transplant procedure.

A representative for the New York City Police Department confirmed to Complex that “criminality is not suspected,” and that an official cause of death will be determined by the medical examiner’s office. The investigation remains ongoing.