The defection comes a few months after Anomaly won the Sony Europe account from Fallon.
Wilsher was promoted to managing director at the agency in 2006. She joined the agency in 200 as an account manager and began her agency career in 1998 with Lowe Lintas.
Fallon recently announced that it is to make 10 redundancies and in a separate move senior creative director Tony McTear is leaving the Publicis Groupe-owned agency.
Fallon was appointed to handle the SeeSaw advertising business last October and was also appointed to work on Innocent. However, the recent acquisition of Cadbury by Kraft raises the question over whether it will retain the chocolate manufacturer’s business.
The agency is also facing a review of its place on the BBC agency roster this year and saw its Asda business handed to sister agency Saatchi & Saatchi last year.