Sarah Michelle Gellar's luscious blonde tresses are suddenly darker, she revealed in an Instagram post . You know what that means, right? The conniving and sadistic Kathryn Merteuil will soon invade our television screens. Cue up the fear.Gellar, who will reprise her classic role in NBC's reboot of Cruel Intentions , announced her dramatic hair transformation on March 4. She used the hashtag #brownhairdontcare, which is a pretty accurate description of the character she'll revisit. Kathryn Merteuil is the epitome of spoiled — and she hasn't gotten better with time, according to reports about the new show's plot.The much-anticipated sequel picks up 15 years after the tragic ending to Annette and Sebastian's love affair. Sebastian is Kathryn's stepbrother, with whom she had a steamy encounter in the movie.The fictional couple, played by real-life divorced parents Reese Witherspoon and Ryan Phillippe, have a son, Bash, who may now be controlled by his wicked Auntie Kathryn.Bash is on a mission to learn more about his parents as his beautiful aunt tries to take control of the family's business. Manipulation will surely be on the agenda.Yes, hopefully it will be as juicy as it sounds. If nothing else, Gellar's darker tresses tell us that her character's heart is still as evil as ever.