The pair will continue to have overall responsibility for the UK, but will also oversee the creative work of 20 offices in 16 countries.
They replace Michael Kutschinski, who was promoted to global chief creative officer in January.
De la Fosse and Wilson will remain in London and report to Annette King, the chief executive of OgilvyOne EAME, and Sam Williams-Thomas, the chief executive of OgilvyOne London.
King said: "Emma and Charlie’s reputation speaks for itself. They are a natural choice to spearhead our growth in the region."