Spotted: An explosion of citrus-hued fashion on the set of Gossip Girl, with Blair (Leighton Meester), Serena (Blake Lively) and their entourage working some very vibrant ensembles. Blair looks the part in a pretty mixed-print Nanette Lepore dress and matching Nancy Gonzalez crocodile tote and Serena, her hipster equivalent, wears a lemon yellow-vest top, navy shorts and bright blue bag. While the stylish twosome kept their footwear neutral, their two sidekicks sported brighter heels with their equally electrifying frocks. And let's not forget the hair accessories: We love Serena's sunny barrette and the sidekicks's schoolgirl headbands. Click through the gallery to see more photos of the stylish cast on set.