As reported on prweek.com/uk (31 October), Nelson Bostock has been called in for the six-figure brief following a competitive pitch.
Mat Sears, head of PR at parent company Everything Everywhere, said there was 'an immediate challenge for the T-Mobile share of voice to grow across traditional media through Q4'.
Everything Everywhere also owns mobile phone brand Orange after a joint venture was formed in 2010 between Deutsche Telekom and France Telecom.
Sears said Nelson Bostock's brief would include highlighting the differentiation between Orange and T-Mobile.
'Their role will be to help us better define the best channels for our target audience, as well as to ensure our brand values are more clear and consistent,' he added.
The agency will first run an audit to gain an understanding of the brand's reputation in online and offline media. This will help set T-Mobile's longer-term objectives.
While the audit is under way, the agency will be leading Christmas PR activities by targeting gift guides in the media with details of handsets and other offerings.
Nelson Bostock will also be required to establish a blogger relations programme.
Sears added that the brand was working on its 2012 strategy, but T-Mobile's 'Life's for Sharing' positioning would remain integral to marketing.
He denied that an appointment had been made for the overarching Everything Everywhere corporate brief, after well-placed sources told PRWeek that the company was in final talks with GolinHarris and Weber Shandwick (PRWeek, 12 August).
Stuart Jackson was recently promoted to director of comms and corporate affairs at Everything Everywhere. Corporate comms director Robin O'Kelly is to leave the company without having announced a new role.