“I had never seen Michelle cry before,” Mara Wilson wrote of Michelle Trachtenberg, who she attended middle school with in California

Mara Wilson is opening up about the deep bond she and the late Michelle Trachtenberg shared as child actors.

Wilson, best known for portraying the title character in 1996’s Matilda, remembered in a recent essay for Vulture how she and Trachtenberg — who died unexpectedly at 39 on Feb. 26 — became childhood friends.

As Wilson recounted, the pair attended the same middle school in Burbank, Calif. after Trachtenberg moved from New York to Los Angeles. Wilson recalled that she was often surprised to hear other students say “they’d heard [Trachtenberg] was mean, full of herself, a total bitch.”

” ‘She’s not,’ I’d say, every time. ‘She’s really nice!'” Wilson recalled telling people, while wondering if other students — many of whom were also aspiring actors — grew jealous of students like Trachtenberg, who made her feature film debut at 11 years old in 1996’s Harriet the Spy. 

Wilson also remembered that in 1999, before Trachtenberg graduated from middle school, Trachtenberg asked her, “Are the kids here mean to you?” “Sometimes,” Wilson recalled saying. “Because they are to me,” she recounted Trachtenberg replying. “They call me Harriet the Slut, Harriet the Bitch, Harriet the Bitchy Spy … and so much worse. They never stop.”“I had never seen Michelle cry before. I’d never seen her anything other than perfectly composed and confident,” Wilson wrote in the piece. “That’s what it was, I realized. That’s why they said she was ‘mean.’ Because they were mean to her first, then when she went on the defense, they called her a bitch.”Wilson wrote that she faced bullying of her own when she began attending high school, over her career as a child actor “and just for being an awkward teenager.” 

Michelle Trachtenberg in 1996. Evan Agostini/Liaison

Even in college, Wilson recalled defending Trachtenberg from an acquaintance who said the actress “just has to be a bitch in real life” based on her performance in Gossip Girl.

Following Trachtenberg’s death, the New York City Medical Examiner’s Office told PEOPLE that Trachtenberg’s family objected to an autopsy; her cause of death has been ruled “undetermined.”

In the weeks since Trachtenberg’s death in February, Wilson said she has began reaching out to many of her childhood acting friends who had also known the Buffy the Vampire Slayer star. “I needed them to know that I loved them and missed them,” Wilson wrote.