Harv Bains, the creative director on the global Sprite account at Johannes Leonardo New York, joined this week in the role of creative director. He previously worked at Fallon.
Aaron Wilmer and Will Flack have also been promoted to creative directors. The duo has been at Brothers and Sisters for five years and previously worked at Karmarama.
The trio will report into Andy Fowler, the founder and executive creative director of the agency.
Fowler said: "With three new creative directors and Matthew Charlton as our CEO, we are ready to challenge for bigger and better opportunities and take our creative work onto a whole new level.
"Harv, Will and Aaron are modern, media neutral CDs with massive ambition."