Washington, Feb. 27 -- Actor Blake Lively paid tribute to her 'Gossip Girl' costar Michelle Trachtenberg, who passed away at the age of 39.

Taking to her Instagram stories, she wrote a long post remembering her co-star. Trachtenberg and Lively both appeared in the 2007-2012 series, with Trachtenberg portraying bad girl Georgina Sparks, a frenemy to Lively's Serena van der Woodsen, reported People.

"This was the first day I met Michelle," Lively wrote in her caption, shared alongside a photo of the two from 'Gossip Girl'. She was electricity. You knew when she entered a room because the vibration changed. Everything she did, she did 200%."

Lively added, "She laughed the fullest at someone's joke, she faced authority head on when she fel...