Blake Lively on Wednesday shared a lengthy tribute to her “Gossip Girl” costar Michelle Trachtenberg, who was found dead in her New York City apartment on Wednesday morning.

Trachtenberg, also known for her roles in “Buffy the Vampire Slayer” and “Harriet the Spy,” had reportedly undergone a recent liver transplant and may have experienced complications as a result. She was 39.

Criminality is “not suspected” in the actor’s death and an investigation “remains ongoing,” police told HuffPost.

Lively, who starred as Serena van der Woodsen on the hit teen drama, shared an image of the first day she met Trachtenberg, who played Georgina Sparks in The CW original series and later reprised the role in its recent rendition on Max.

“She was electricity. You knew when she entered a room because the vibration changed. Everything she did, she did 200%,” wrote Lively on her Instagram Stories alongside the snap from Season One’s “Desperately Seeking Serena” when Georgina returns to New York City.

“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 continued,” She was fiercely loyal to her friends and brave for those she loved, she was big and bold and distinctly herself.”

Lively added that her late costar always had “yummy caramel smelling lipgloss on because she didn’t just want to sparkle on camera,” she wanted to make for a nice experience down to the “subtle smell of her lipgloss because she cared about the sweet details.”

“She was a kind person, through and through,” she wrote.

“Time passes. 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.”

She concluded by reminding her followers to hold their loved ones dearly and noted that the world “lost a deeply sensitive and good person” in Trachtenberg.

“May her work and her huge heart be remembered by those who were lucky enough to experience her first,” she continued.

Other “Gossip Girl” actors honored Trachtenberg on social media including Ed Westwick, who shared a picture of his late costar alongside a prayer emoji on Instagram Stories.

“It’s been a long time since I’ve seen Michelle but I remember a talented, sharp, funny and warm soul,” wrote Westwick, who portrayed Chuck Bass on the show, in a statement to People magazine.

“Thinking of her and the family. So sad.”

Chace Crawford, known for his role as Nate Archibald on “Gossip Girl,” declared that Trachtenberg was “one of a kind” in an Instagram post featuring several snaps of the two.

“I remember her coming on set for the first time and just absolutely owning it. She was a force of nature and just so so unapologetically funny and magnetic.. remembering those years with a big smile,” he wrote.

“Just a terrible loss. Love you ❤️.”

“Gossip Girl” creators Josh Schwartz and Stephanie Savage also described Trachtenberg as “so funny, kind, and talented” in a statement shared with People magazine.

“Her portrayal of Georgina Sparks was an iconic fan favorite, and grew from a one season villain to a beloved character who returned over the course of six seasons. She was a delight to have on set and will be deeply missed. Our thoughts are with her family.”