Sarah Michelle Gellar took a walk down memory lane in honor of her late friend and co-star Michelle Trachtenberg.

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

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

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

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

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

Blake Lively, Sarah Michelle Gellar, David Boreanaz, Ed Westwick, Kim Cattrall, Kenan Thompson, Melissa Joan Hart and more ...

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

Sarah Michelle Gellar is paying tribute to her 'Buffy the Vampire Slayer' costar Michelle Trachtenberg after her death at 39: ...

News of Michelle Trachtenberg's death prompted tributes from her friends and former "Buffy," "Harriet the Spy," and "Gossip ...

Nicholas Brendon, Alyson Hannigan, Charisma Carpenter, and others also paid tribute to their former costar after her tragic ...