Stewart conceived the company after an increasing number of artists complained of becoming disillusioned with dealing with large corporate enterprises.
Artist Network aims to offer a collaborative, integrated environment in which artists across the music, film, TV, art and literature industries work together in a single company. It has offices in London, Los Angeles, St Petersburg, Bombay, Shanghai and Kingston, Jamaica.
St Luke's will expand to be a broader creative company, offering client-funded television and film sponsorship and programming, event management, broadband content creation and merchandising, and propriety ownership of multi-media ideas. Its sister design company, Glue, will offer online capability.
Law said: "St Luke's is now the business-to-business arm of an ambitious creative media company. No-one really knows how advertising will develop but to suggest it will organically grow into established areas such as television programming is plain nonsense. Agencies will need to look beyond themselves and into strategic partnerships."
Artist Network has already signed eight music acts, including the reggae artist Jimmy Cliff. It is also working on two feature films and three television programmes.
Law recently handed over the day-to-day running of St Luke's to the newly promoted joint managing directors, Neil Henderson and Phil Teer, to allow himself time to concentrate on the Artist Network venture. "Artist Network is as big to me as when we first started the agency,