Polly Cochrane, Channel 4 director of marketing, said Branded would oversee brand strategy right across the company, with particular emphasis on its long-term direction across video-on-demand and mobile channels.
The projects will be led by Branded's executive director Chris Herd, the former Bates UK managing director.
According to Cochrane, Channel 4 has to diversify if it wants to have the same cultural impact post digital switchover as it has today.
Cochrane said: "With diversification comes the threat of brand dilution. Branded will help us articulate the role of the 4 brand in a digital future, while ensuring that our brand values are to the fore in any new ventures launched along the way."
Philip Ley, founder and managing director of Branded, said the appointments reflected Branded's understanding of the opportunities presented by new platforms and its insights into how TV will be consumed in the future.
He said: "Going forward, this will be critical in the development and positioning of the Channel 4 brand.
"Our primary role will be to stimulate thinking on how Channel 4 should be adapting to the new digital revolution."
Branded's clients include Yahoo!, RTE and the Lawn Tennis Association, as well as Channel 4.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .