The actress played socialite Georgina Sparks on the hit CW series Michelle Trachtenberg’s Gossip Girl costars, Ed Westwick and Chace Crawford, are paying tribute to her after her sudden death at age 39.

Georgina was played by the actress Michelle Trachtenberg, who was found dead at 39 in her Manhattan apartment on Wednesday. Her performance as the teenage supervillain brought an arch flair to a character who was only a minor figure in the novels that were the basis for the show, but became a fan favorite onscreen.

Trachtenberg starred as the cunning Georgina Sparks on the beloved CW series, appearing in each of the six seasons and reprising her role in the recent reboot.