Freemantle will be given specific client responsibilities and a remit to develop Universal McCann's communications planning product on a regional basis.
Freemantle, who starts in the newly created role in January, will report to the Universal McCann EMEA president, Graham Duff.
Duff said: "Freemantle has the right credentials and the right personal qualities to accelerate our product in order to ensure we continuously deliver breakthrough marketing communication solutions for our clients."
Freemantle has had two spells at Carat. In her second stint, which began in 2002, Freemantle was responsible for providing international communications strategies for Renault, Beiersdorf and SCA. She also helped develop Carat's global "3C" communications planning programme.