Seward Perry will be joined by former media director of Crispin Porter & Bogusky, Amy Sheil, as partners of a new 30-strong team.
Paul Woolmington, founding partner of Naked New York, said: "Both Lisa and Amy have proven track records for applying unparalleled creativity and strategic excellence to communications planning. Their addition will not only increase Naked's bench strength, but will also bring us a fresh perspective and help us continue to pave the future of communications planning."
Naked moved the goalposts for what a communications agency can do when it launched in London in the summer of 2000.
Its full-service branding, web and communications offering paved the way for more integrated marketing solutions and it now operates in 15 offices and 12 countries around the world.
Previous campaigns for global clients include American Express, Coca-Cola, Dunkin' Donuts, Google, Johnson & Johnson, Kimberly-Clark, Kraft Foods, NBC Universal and Samsung.