Actresses Zhou Xun (L) and Gao Yuanyuan ride a bus as they experience the public transport network in Beijing on July 16, 2008. [Photo: stardaily.com.cn]

Less driving and more walking. That's what some Chinese celebrities are doing to welcome the Beijing Olympics.

Zhou Xun, Chen Kun, Gao Yuanyuan and Tong Dawei hit the road on Wednesday to experience the public transport network in Beijing. They started from the Temple of Heaven in the central-southern part of the city and reached the Bird's Nest in northern Beijing by bus, the metro and bicycles in about an hour.

Charles Zhang, CEO and president of Sohu.com and organizer of the event, joined the stars for the 20-kilometer journey.

"If we drive less, we would be contributing to the green Olympics," actress Zhou Xun, an environmental ambassador for the United Nations Development Program, told China News Service.

Actor Chen Kun says it's been five years since his last subway ride, and this time he found that Beijing's subway service was not only comfortable but also convenient. "During the Olympics, the venues will be accessible by subway or by bus. It's convenient and environmentally friendly."

With the Olympics less than one month away, Beijing is gearing up to further expand its public transportation network. Three new subway lines will be opened later this month, including the Olympic branch line that connects the major venues.

The operation time of more than 350 bus routes will be extended, and 34 new routes will be added, according to previous reports. Olympic ticket holders will be able to ride certain buses and subway lines for free during the Games, according to Xinhua news agency.