A group of supporters called Roy-BoyCool had cruised along the Wulong River, one of the waterways that flow into Dianchi Lake in Yunnan province, collecting waste for recycling and keeping tabs on water quality. The lake on the Yunnan-Guizhou Plateau has been facing pollution woes in recent years.

"You have been to so many places contributing to the public good. We promise to do good work with you.… We are doing our part to help save Dianchi Lake for you," Roy-BoyCool members posted online in early November.

Other public projects carried out by Wang's fans include building three libraries in Guangxi and donating 1,600 books, planting 1,108 trees in Northeast China to mark Wang's birthday on Nov 8, and holding a concert to collect donations for autistic children.

Wang said at his birthday concert in Beijing on Nov 20 that he was proud of what his fans have done.

"Public welfare is what I've always wanted to do. I hope that under my influence, people can pay more attention to charity," Wang says.

At the concert, TV host and singer Yang Yang said Wang "takes responsibility as a teen idol. He leads people into doing a lot of meaningful things. I believe that this love and responsibility will be passed on to more people under his call."

In October, Wang and his team set up the Yuan Foundation, which aims to garner social action and goodwill to help people in need. Wang became one of the youngest Chinese singers to establish a charity fund.