Pop icon Elton John publicly dedicated his only concert in Beijing to Chinese artist and political critic Ai Weiwei.

That sent a murmur of shock through an audience accustomed to tight censorship of entertainment.

Minutes into a more than two-hour show Sunday night, John told the audience that the performance was dedicated “to the spirit and talent of Ai Weiwei,” according to several audience members. They said the crowd rumbled in recognition that Ai remains a touchy subject for the Chinese government.

The internationally acclaimed sculptor and installation has used his art and his renown to draw attention to social injustice in China. He was detained for nearly three months last year, and he remains barred from leaving China.

The Chinese government exercises tight control of live performances, requiring artists to submit detailed lists of songs, casts and crew members before approval is given.