The founders are also looking to recruit a third partner to build the data and technology backbone of the agency.
Infectious will seek to win business from clients with small-to-medium-sized online spend of around £2 million, and is looking to build partnerships with digital creative agencies in a bid to bring in business.
The agency, which is due to launch on 19 May, aims to capitalise on developments in digital media such as the rise of social media and behavioural targeting.
Kelly said: "There are a multitude of changes taking place across the internet and digital media markets. The pace of change is not slowing as the market matures, it's actually getting quicker."