Basketball star Yao Ming and British entrepreneur Richard Branson on Thursday launched a campaign urging Chinese to stop eating shark fin soup to help save the predators.
Shark fins are used in a thick soup that is viewed as a delicacy by Chinese people and served at luxury restaurants in China, Hong Kong and Taiwan.
The method of shark-finning - slicing off the fins of live animals and then throwing them back in the water to die - is condemned by animal rights campaigners and blamed by scientists for a worldwide collapse in populations.
The campaign, launched in Shanghai, includes advertisements featuring the two celebrities and a website for people to make an online pledge to stop eating the soup, said the organiser, international conservation group WildAid.
Yao, who retired from the sport in July but remains one of China's biggest sporting names, made a pledge to stop eating shark fin soup five years ago and has since served as an ambassador for WildAid, the group said in a statement.
Branson is backing the campaign through his non-profit foundation Virgin Unite.
"I simply cannot imagine a world without sharks - we must not let this happen," he said in the statement.
WildAid, which seeks to halt the trade in wildlife, estimates up to 73 million sharks are harvested annually, mainly for shark fin soup.
"The ongoing and increasing demand for shark fin is holding many species on the brink of extinction, further threatening marine ecosystems the world over," it said.
Earlier this year, a member of China's parliament proposed a ban on the trade in shark fins.
Ding Liguo, a businessman delegate to the National People's Congress, said China should lead the world in banning the trade since 95 percent of shark fin is consumed in mainland China, Taiwan and Hong Kong.