The agency is understood to have picked up the business without a pitch. It already held a place on the Ferrero roster after winning the company's flagship Ferrero Rocher brand in August, following a pitch against Mortimer Whittaker O'Sullivan and St Luke's.
WCRS was previously the incumbent on the Tic Tac advertising account. The agency had worked on the business since 2002, but resigned it in June this year, citing "creative differences".
During its time working on the business, WCRS was responsible for moving the mint brand away from its "Shake your Tic Tacs" strapline, introducing a new "Full of refreshing little lifts" positioning.
Tic Tac was in the public eye last year after a technical error meant that an ad for the brand interrupted coverage of an FA Cup fourth-round replay between Everton and Liverpool, just as Everton's Dan Gosling scored the match-winning goal deep into extra time.
Despite being ITV's error, Tic Tac subsequently released a humorous 20-second viral that saw men dressed as orange and lime Tic Tacs re-enact Gosling's strike on Hackney Marshes.
MEC handles Tic Tac's media planning and buying.