The pair have also confirmed that Manning Gottlieb OMD has taken a minority stake in the business.
Goodstuff has also just added the Independent Radio News brief to its Virgin Mobile and Ann Summers planning accounts.
The agency offers full-service communications planning, insight and strategy and advises on branded content and brand partnerships.
Stephens said: "When Andrew and I were presented with the opportunity of launching our own agency, we took a good look at the evolving market and set about creating a rounded proposition for changing client needs and expectations."
Goodstuff's recent work includes advertiser-funded programming for Virgin Mobile and an ambient campaign for Ann Summers, promoting the Rampant Rabbit vibrator.
James Kydd, the brand director at Virgin Mobile, said: "In only a couple of months, Goodstuff has delivered some great ideas in advertiser-funded programming, content and brand alignments."