Unity is working with the charity's street fundraising team and green theatre company Arcola to produce ten-minute plays on the issue of biofuels.
Members of Arcola will perform these plays in a range of unusual venues including the Innocent festival and Thames barges throughout August and September.
Unity hopes the choice of venues will generate press coverage.
Agency co-founder Nik Done said that street fundraising was an 'interruptive' form of marketing, like traditional advertising.
Instead, the agency has 'taken our core principle of engagement marketing and put a twist on it to make it work for street fundraising'.
FoE is ramping up its campaigning on biofuels this summer.
Unity secured coverage last month for a climate change gig with Razorlight's Johnny Borrell.