Portas, the creative communications shop founded by the eponymous retail expert, won the account after a competitive pitch.
The agency will be responsible for Goldsmiths’ brand strategy, advertising and digital activity. Its first task will be to launch the retailer’s in-house jewellery collections with the strapline: "It starts with Goldsmiths."
The work will be unveiled in August. Ruth Benford, the executive director of marketing at Goldsmiths, said the agency’s appointment marked an "exciting new business era where we look to evolve from a retailer into a luxury aspirational brand".
"Portas’ passion and understanding of our business and what makes brands culturally relevant made the agency a natural choice," she added.
Goldsmiths is one of four jewellery and watch retail brands owned by Aurum Holdings.
The others are Mappin & Webb, Watches of Switzerland and the concept store Boutique.Goldsmiths. The group is the UK’s largest distributor for Rolex, Cartier and Breitling.
Caireen Wackett, the managing director of Portas, said: "There’s an opportunity for Goldsmiths to carve out a unique place and we’re excited to be working with it to deliver this ambitious vision."