OgilvyOne's campaign will run for six months and will form the main focus for Action Aid during its autumn and winter recruitment drive.
The work aims to build brand awareness of Action Aid and emphasise the power that ordinary people have to help the charity change lives.
The campaign will centre on a DRTV ad, which will be supported by digital executions.
Action Aid works in 49 countries and is the UK's highest-income child sponsorship charity.
Sue Bishop, Action Aid UK's communications director, said: "We owe it to the thousands of people we work with in the world's poorest communities to inspire more people to become sponsors. By combining the stories of our work and OgilvyOne's creativity, I'm sure we will."