Jackie Chan has joined Hong Kong pop idols Charlene Choi and Gillian Chung in the cast of Emperor Multimedia Group's The Twins Effect.

In addition, EMG announced that Sydney-based production and sales house, Arclight Films, will represent the film, which started shooting in Hong Kong on Tuesday, in all territories outside Asia.

The action horror stars singing sensations Chung and Choi - known collectively as Twins - as high-kicking schoolgirls who are called on to battle a horde of vampires. Jackie Chan makes a special appearance as a bus driver who becomes the girls' kung fu master.

Dante Lam (Beast Cops, Hit Team) is directing the film with Donnie Yen (Hero, Blade 2) as action director. The cast also includes Hong Kong stars Edison Chen, Ekin Cheng, Anthony Wong and Josie Ho.

"We were happy to represent the film from its early days, but Jackie Chan's involvement takes it to a whole new level," said Arclight chief Gary Hamilton.

Arclight will also co-produce and handle international sales on EMG's upcoming big-budget actioner, Kung Fu Master, set to star Yen. The English-language film is likely to shoot in China from next spring and may also involve a Canadian partner.

EMG has a twin-track strategy under which it produces films aimed at the international market - including The Twins Effect and $40m Jackie Chan actioner Highbinders - along with smaller, domestic projects. It recently released dramas Just One Look, also starring Twins, and Demi-Haunted in the Hong Kong market.