Trachtenberg, who co-starred with Gellar on the hit TV series, was found dead in her apartment on Tuesday. She was 39.

Michelle Trachtenberg’s former “Buffy the Vampire Slayer” costar Sarah Michelle Gellar is looking back at their time together ...

Sarah Michelle Gellar is paying tribute to her “Buffy” sister, Michelle Trachtenberg, who died on Feb. 26 at 39 years old.

Sarah Michelle Gellar is paying tribute to her late "Buffy the Vampire Slayer" co-star Michelle Trachtenberg after her tragic ...

Sarah Michelle Gellar, Taylor Momsen and Blake Lively are among those paying tribute to Michelle Trachtenberg, who died ...

Nicholas Brendon, Alyson Hannigan, David Boreanaz, and others paid tribute to their former costar after her tragic passing on ...

Sarah Michelle Gellar mourned the death of “Buffy the Vampire Slayer" co-star Michelle Trachtenberg in an Instagram post.

Cast members of "Buffy the Vampire Slayer," "Gossip Girl" and more are remembering their co-star Michelle Trachtenberg​ after ...

Sarah Michelle Gellar has paid tribute to her former Buffy The Vampire Slayer co-star Michelle Trachtenberg following her ...

Friends and costars of Michelle Trachtenberg are remembering the actress with touching tributes after her passing on ...

Blake Lively, Sarah Michelle Gellar and other Hollywood figures are paying tribute to Michelle Trachtenberg, who died at 39.

Fans and friends alike are mourning the loss of Michelle Trachtenberg, who died this week at age 39. Sarah Michelle Gellar ...