BBDO joined P&G's roster when the consumer products giant bought Gillette. Since then, Andrew Robertson, the BBDO global chief executive, has made growth of P&G business a priority.
The deal represents the first major acquisition for BBDO since 1987, when it bought the Chicago agency Cohen & Greenbaum, now part of Energy BBDO.
Robertson denied the agency had been acquired because of its P&G connections. "Clients' business is not for sale, it has to be earned," he said.