Heather Graham and Sarah Michelle Gellar attend the Filming Italy 2025 photocall at Forte Village Resort in Santa Margherita di Pula, Italy on June 21. Fun in Aspen. C2 Photography/FOOD & WINE.

Michelle Trachtenberg’s former “Buffy the Vampire Slayer” costar Sarah Michelle Gellar is looking back at their time together on screen and off, one day after Trachtenberg died in New York City.