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, alongside agencies such as Abbott Mead Vickers BBDO and Ogilvy & Mather.
Mother has worked on Motorola in the past through the company'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 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. It was originally scheduled to launch in September 2006.