38 Iconic Duo Halloween Costumes

This stylish duo costume idea is for all the Upper East Siders out there. Dress in your finest designer outfits — or thrift store dupes, for the more budget-friendly route — to mimic Serena and Blair's looks for Halloween.

• What to wear for Serena: White hat, costume jewelry, flowy pastel pants, and some designer shopping bags.
• What to wear for Blair: A cute but high-fashion dress, a Birkin, and some Chanel shopping bags. Don't forget the headband.