HOUSTON, Feb. 15 (Xinhua) -- Former NBA star Yao Ming was officially named Goodwill Ambassador of the U.S. city of Houston Friday by the city's mayor at a ceremony here.

Yao, the former Rockets center who lived in Houston for ten years, was also given key to the city by Mayor Annise Parker at the ceremony in downtown Houston.

Yao was appointed as Houston's Goodwill Ambassador because of "the outstanding success" he has had as a professional basketball player for the Rockets since 2003 and the eight years he has participated in the All-Star Games, as well as the international connections he has fostered and the cultural enhancement he has brought to the Houston community, read an proclamation from Parker.

The title is also a recognition of the contributions Yao has made and is making "through unselfish public service for the benefit and welfare of humanity," the proclamation said.

"Houston has been enriched by your presence and is grateful for your dedication to improving the cultural fabric of our city," it said.

Yao, who retired in 2011 after having played with the Rockets for nine seasons, was back in Houston from China for the NBA All-Star game as a judge of the Slam Dunk Contest.