Kungfu movie star Jackie Chan offered the public a "deep bow of apology" after his son, actor, singer and socialite Jaycee, was arrested in Beijing for drug use.
Jackie Chan, 60, served as a goodwill spokesman for the China National Anti-Drug Committee in 2009, promoting anti-drug education.
Jaycee, 32, was arrested on Monday after police found 100 grams of marijuana in his apartment, they said.
"As a public figure, I'm ashamed and distressed," Chan wrote on his Chinese-language microblog on Wednesday. "His mother is especially heartbroken.
"Along with Jaycee, I want to take a deep bow of apology to the public."
The younger Chan is the latest celebrity caught up in a campaign against drugs in China, which has vowed to purge the country's elite of decadence and other social vices.
Corruption and excess among the upper class are a prime source of social discontent as a yawning gap between the poor and the wealthy widens.
The use of drugs in China, particularly synthetic drugs like methamphetamine, ketamine and ecstasy, has grown along with the rise of a new urban class with greater disposable income.
Last week, a group of 42 entertainment management firms said they had signed a deal with Beijing police that they would not work with celebrities who used drugs, the state-owned Beijing News reported.