The agency, which was launched last June by the former Manning Gottlieb OMD directors Andrew Stephens and Ben Hayes, will help drive the jeans manufacturer's below-the-line activity in the UK by developing plans to talk to consumers at a grassroots level.
Goodstuff's appointment will not affect Starcom Motive's position as the agency of record on Levi's media planning and buying account.
Scott Morrison, the UK head of marketing at Levi's, said: "We have been talking to Goodstuff about working with us as an ideas agency. We chose them because they have a track record of developing great ideas for great youth brands."
Goodstuff's other clients include Virgin Mobile, Ann Summers and the underwear retailer Knickerbox.
Although it remains the market leader with more than a 20 per cent share of the sector, Levi's sales were down 1 per cent in 2004, compared with the previous year.
The jeanswear market in the UK has grown to be valued at £1.6 billion, primarily driven by product inn-ovations that are aimed at female consumers.