Havas Sports & Entertainment has been looking to increase its global offer through an acquistion strategy, as major sporting events including the Olympics, Paralympics, Euro 2012 and the 2014 World Cup in Brazil near.
Ignition is handling the Olympic Torch Relay for the London 2012 Games.
It was founded in Vermont by Dill and Suan Driscoll in 1997. It has offices in Atlanta and New York and counts American Express, BP, ESPN, United Nations Foundation and Victoria's Secret among its clients and is a "global partner" of The Coca-Cola Company.
Havas Sports & Entertainment is the brand engagement arm of Havas, which also includes the Cake agency, working with brands scuh as adidas, British Airways, EDF, Ikea and the recently won Eurostar account on sponsorship, content creation and brand experiences.
Ignition will continue to be managed by current president Mike Hersom and the original founders. Hersom will report into Havas Sports & Entertainment's global president and chief executive officer, Lucien Boyer.
Boyer said: "Ignition will add tangible value to the Havas Sports & Entertainment and Cake Group agencies in our network, helping to reinforce our strong global offering at a very interesting time for brands in sports and entertainment."