
Rocawear will only be available in the flagship Oxford Street store. Other brands available include Boxfresh, Lee Jeans, and the fashionable luggage brand Eastpak. Items will be available in a dedicated area of the store called The Studio.
Initially the full fashion range will be in 38 of HMV's larger stores in London, Leeds, Manchester, Liverpool, Birmingham, Southampton, Cardiff, Glasgow, Belfast and Dublin.
Smaller stores will carry a limited selection of T-shirts and accessories and fashion will be added to hmv.com at a later date.
With the longer-term future of CD and DVD sales looking gloomy, HMV is moving into other areas in an attempt to position itself as a broad-based entertainment brand rather than a high street-retailer.
It sponsors live music venues and festivals, has moved into cinema and now offers digital downloads.
HMV is backing the launch of The Studio with live events by the band Everything Everything and rapper Kano, who is sponsored by Boxfresh.
Richard Stockwell, HMV fashion manager, said: "Music and fashion can be a perfect fit for HMV, not least because they overlap and influence each other so strongly these days. And, of course, we now also own a number of music venues and festivals in addition to our stores, so our brand is even more uniquely placed to create a compelling retail offer to our customers and a cool environment for them to shop in."