The agency won the business in a pitch for a trade and relationship marketing programme that involved four unnamed non-roster shops.
The account will involve the development of a customer loyalty programme across all of the Nescafe brands, including Nescafe Original, Gold Blend, Decaff and Half Caff.
The agency will develop integrated activity, including digital, direct marketing and sales promotion, as part of Nestle's £15 million investment in its Pick Me Up loyalty scheme.
The programme was set up last year to deliver more targeted communications to customers and is designed to encourage customers to increase their spend across the Nescafe range. The scheme will extend to include the Fine Blend brand next year.
Joshua is expected to link the loyalty activity with the beverage brands' advertising, which is handled globally by McCann Erickson.
In the UK, Nescafe's advertising centres on a campaign that features the TV fashion gurus Trinny Woodall and Susannah Constantine.
The CRM programme is part of a push by Nestle to reinvigorate the instant coffee market.
Sales of instant coffee fell by nearly 13 per cent between 1999 and 2003, while ground coffee increased its share of the UK coffee market from 11 per cent to 14 per cent, according to Mintel.
Last year, Nestle overhauled its luxury instant coffee brand Gold Blend.
The brand was reformulated to give it a "richer aroma" and repackaged to bring it into line with the designs created for the food giant's luxury coffee brands Blend 37, Black Gold, Alta Rica, Cap Colombie and Kenjara.
A £4 million TV campaign by McCann Erickson supported the relaunch.