Andy Lau's Focus Films is co-financing a $5m (HK$40m) gangster thriller, Jiang Hu, which combines a stellar cast with one of Hong Kong's most promising new directors.

The film, which started shooting earlier this month, reunites many stars from recent Hong Kong blockbuster Infernal Affairs including Lau himself, Eric Tsang, Edison Chen, Shawn Yue and Lam Ka-tung. In addition, Jacky Cheung (July Rhapsody) and mainland newcomers Xiao Hai and Lin Yao have joined the cast.

The director, Wong Ching Po, is also a newcomer, but his first feature Fu Bo - a grisly drama about a mortuary assistant, a triad assassin and a chef who cooks for death row convicts - was critically acclaimed. Wong is also a three-time winner of the Hong Kong Independent Short Film Festival.

Jiang Hu (literally "triad society") tells the story of the chaos that ensues when a triad kingpin decides to go into retirement. Chen and Yue play two young thugs who are eager to move up the triad ladder.

The film marks the first time that Lau and Tsang have invested in a project together. Tsang's Anytime Pictures, investment group Good King and Shenzhen Film Studio are producing while Focus Films is handling international sales. Go Film Distribution will handle the film in Hong Kong. Media Asia has a minority investment.

Lau founded Focus last year to co-finance and distribute local and international movies. The company has already produced two titles - youth drama Summer At 17 and romantic thriller Life Of Intimacy, starring Tony Leung Ka-fai and directed by Vincent Chui