The agency will be called Lucidity Mobile and will specialise in strategy, media and creative services.
It will offer clear and transparent advice on the mobile ad industry, and combine in-depth knowledge on mobile with solid brand planning to help advertisers navigate their way through the options available.
Fieldhouse said: "We’re not tied to any particular mobile solution, hence clients will get an impartial view from us on what is best for their brand. We will be able to tell clients what works, what doesn’t and how mobile can be integrated into the rest of their communications plans."
Though Lucidity Mobile has not secured any clients for its launch, Fieldhouse confirmed it is speaking to a number of undisclosed potential clients and is offering strategic advice on mobile to global private equity firm Warburg Pincus.
Fieldhouse is an active member of the mobile industry and has sat on the mobile steering group of the Internet Advertising Bureau. He will continue to work with MediaCom and M4C, the agency set up by WPP to handle the Central Office of Information account, two days a week.
To prevent competition issues, Lucidity Mobile will not approach any MediaCom clients, although Fieldhouse is expected to reduce his commitment to MediaCom over time.
Fyfe was previously head of emerging platforms at MediaCom and has added mobile to his responsibilities.
Before he joined MediaCom in 2008, Fieldhouse led the agency sales team at the mobile company Incentivated. He started his career in the radio industry at the Radio Advertising Bureau and then moved to Emap Advertising (now Bauer Media).
Fieldhouse takes the role of strategy director and co-founder at Lucidity, with his business partner, commercial director and co-founder David Philippson. Philippson has 10 years' experience in the software industry and has launched two online e-commerce businesses.