The agency won a pitch to work on promoting Mobile by Sainsbury’s, a new company set up by the pair, until December.
The venture sees Sainsbury's follow in the footsteps of Asda Mobile, which also uses the Vodafone network, and Tesco Mobile, which uses O2.
Cake associate director Helen Rainford will lead the account and report to Mobile by Sainsbury’s brand comms manager Lucy Wilkinson and marketing director Emma McLaughlin.
The agency's account director Kelly Grindle said: ‘We will be targeting mums and families. One of the benefits of Mobile by Sainsbury’s is it is based on trusted brands, and a key part of it will be offering simple pricing plans and a reliable network.’
Following the announcement of the service on 1 July, Mobile by Sainsbury’s launched last week with a range of pay-as-you-go packages, with the cheapest costing £10.
McLaughlin recently told Marketing the proposition was based around its target audience wanting ‘freedom and transparency’.