The agency starts work on the account this week, and it will be headed up by associate director Jessie Wales.
The new account will boost the agency’s existing fashion portfolio, which includes Kangol, Silhouette and Rocket Dog.
Brandnation’s managing director Mary Killingworth said: "Our strong combination of fashion, sport and retail expertise helped us land this prestigious account. We will be working with an exciting brief for this fast-growing company with ambitious plans for 2015 and beyond."