Julian Cheung held a concert at Guangzhou on 16 January.
Towards the end, his wife Anita Yuen came up to the stage and sang "Need you every minute" with Julian while holding hands, reported Asian E-News Portal.
At the last line of lyrics, Julian let Anita sing the last character and she surprisingly sang it using a male voice, causing the audience to erupt in laughter.
Anita happily said she was emotional when she thought Julian remembered the lyrics to "Fiancee" but she later found out that he was reading lyrics off the screen.
Julian wittily said: "I am cultured, of course, I can read words."