Blake Lively mourned the loss of her “Gossip Girl” co-star Michelle Trachtenberg after the latter tragically died on Wednesday.

“This is the first day I met Michelle,” the actress wrote via her Instagram Stories on Wednesday, alongside a photo with Trachtenberg.

“She was electricity. You knew when she entered a room because the vibration changed. Everything she did, she did 200%.”

“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,” Lively, 37, added.

The “Age of Adaline” star described Trachtenberg as “fiercely loyal to her friends and brave for those she loved.”

She also recalled how the “Buffy the Vampire Slayer” star would carry caramel-scented lipgloss because she “cared about the sweet details.”

“Time passes,” Lively added. “You take for granted that you get the chance to see an old friend. To paraphrase, the real tragedies in life are the ones that blindside you on an idle Tuesday.”

The “It Ends With Us” star concluded, “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.”

Trachtenberg was found dead in her New York City apartment after going into cardiac arrest on Wednesday. She was 39.

The “Ice Princess” star was found “unconscious and unresponsive” by first responders and declared dead at the scene.

Trachtenberg’s official cause of death has yet to be revealed, though she recently underwent a liver transplant.

Lively referred to the Disney alum as “loyal” after Trachtenberg denied commenting on her ongoing legal battle with Justin Baldoni.

In January, the “Inspector Gadget” star shared a selfie via Instagram of her wearing glasses, captioning it, “It takes a lot of strength to see through all the b*llshit. And some dark sunglasses.”

A fan who runs a celebrity fashion account then commented, “Would love to see you release a statement on the Blake drama ❤️ Or idk if this is a direct statement? Hahaha you’re so fabulous.”

Trachtenberg replied, “gosh. Im busy worrying about real world news and families who have no home anymore from the LA fires. But you do you. 🙄.”