Hawkes joins the agency's London board following his retirement from McDonald's in January this year. He will work in an advisory capacity, providing the board with the experience gained from 22 years of being a client.
Bruce Haines, the group chief executive of Leo Burnett, said: "Today's business environment is ever more complicated and pressured for clients and agencies alike. His advice can only help our ability to deliver service at the highest level."
Hawkes started his career at McDonald's and has had responsibility for developing marketing across Europe. He was also part of the team that developed the McDonald's global brand positioning.
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