Blair's secret confidant and romantic interest.
Serena enlists Charlie to investigate Dan and Blair's activities. [S4E19] Petty in Pink
Serena becomes suspicious of the amount of time Dan and Blair are spending together. Blair's secret confidant and romantic interest
The suspicious friend orchestrating the investigation. [S4E19] Petty in Pink
At a high-profile party, Charlie captures a video of Dan and Blair kissing.