Hong Kong actor Andy Lau attends a news conference to promote his upcoming movie 'Protege' in Hong Kong Thursday, Aug. 3, 2006. (AP Photo/Kin Cheung)

Andy Lau may play a major narcotic dealer in the upcoming movie "Protege," but the Hong Kong star had little to say when asked if he had tried drugs to prepare for the role.

Director Derek Yee told reporters at a news conference that one of the movie's stars, Chinese actress Zhang Jingchu, had wanted to try drugs to better portray a drug user but that he talked her out of it.

Zhang denied the claim.

But Lau - who plays a heroin kingpin grooming his successor to take over the business - stayed silent. As did co-stars Daniel Wu, Louis Koo and Anita Yuen.

Publicity material for the film claims the actors took career risks by signing on for a movie revolving around drugs. "All the five stars ... are willing to forsake their star images to have breakthrough performances," a press handout says.

The actors said during a news conference on Thursday that they did extensive research for their parts. Both Zhang and Koo said they met recovering drug addicts. Yee said he had met former drug dealers referred to him by police contacts.

But asked if they had considered trying drugs to prepare for their performances, or if they had ever used drugs, they fell silent.

"Protege," backed by financing from England, the U.S., China, Hong Kong and Singapore, is due to be released early 2007.