Penn Badgley remembers late 'Gossip Girl' co-star Michelle Trachtenberg

When she passed, many took to social media to write tributes, including those who worked with her on Gossip Girl.

"Michelle was one of a kind. I remember her coming on set for the first time and just absolutely owning it," Chace Crawford wrote. "She was a force of nature and just so so unapologetically funny and magnetic.. remembering those years with a big smile. Just a terrible loss. Love you." 

Taylor Momsen shared that she was "in shock" over losing the friend that she met 17 years ago, adding, "She was smart and sassy, bold and sensitive, funny as f--- and filled with fire. She was simply awesome. I’ll miss our late night calls that no one should ever hear but us. She was always in my corner and there to support me whether I was right or wrong. I will miss you everyday my love..I think we truly understood each other and I am so grateful to have had a friend like you in my life for so long..You were a true friend to me which is a rarity in this world and I can’t believe I won’t hear your voice again..I hope you’re f--- up heaven for both of us..I love you so much Michelle, my heart is on the floor. I’m still in shock but I needed to honor her, she deserves more than this. I grieve with all her fans around the world, and my heart is with her family and loved ones. I have so much to say, but she’s the only one I’d want to say it to, my love to you all."

Blake Lively called Trachtenberg "electricity," sharing on her Instagram Stories, "You knew when she entered a room because the vibration changed. Everything she did, she did 200%. She laughed the fullest at someone’s joked, 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, she was fiercely loyal to her friends and brave for those she loved, she was big and bold and distinctly herself."

"The world lost a deeply sensitive and good person in Michelle," the actress continued. "May her work and her huge heart be remembered by those who were lucky enough to experience her fire."

Ed Westwick said on his Instagram Stories that he was "so sad to hear of" her passing and that he was "sending prayers."

Trachtenberg was found in her New York City home, and it was later confirmed that she died from complications of diabetes, according to the New York City Medical Examiner's Office.