The agency is working with senior Motorola executives at the company's Illinois headquarters on what is understood to be a global brief.
The project rekindles Mother's relationship with the Motorola vice president for global retail and channel marketing, Jeremy Dale. The agency previously worked with Dale when he was the marketing director at Orange.
A source close to the account said the project would be a prelude to an official position on the Motorola roster, where Mother will join agencies including Abbott Mead Vickers BBDO and Ogilvy & Mather.
The agency has worked on Motorola advertising in the past through the mobile manufacturer's involvement with Bono's Red charity venture.
Mother was appointed to handle the launch of the Red-branded Motorola handset in May 2006, but a TV spot directed by the Academy director Jonathan Glazer has still not aired. The ad featured two naked black bodies evolving from a lump of clay as they spin on a potter's wheel and was originally scheduled to launch in September 2006.