China Olympic ceremony star mimed

The show's musical director said Lin was used because it was in the best interests of the country.

The revelation follows news that a fireworks display used during the opening ceremony was apparently faked.

'Smiling angel'

Speaking on Beijing Radio station, musical director Chen Qigang said the organisers needed a girl with both a good image and a good voice.

They faced a dilemma because although Lin was prettier, seven-year-old Yang had the better voice, Mr Chen said.

"After several tests, we decided to put Lin Miaoke on the live picture, while using Yang Peiyi's voice," he told the radio station.

"The reason for this is that we must put our country's interest first," he added.

"The girl appearing on the picture must be flawless in terms of her facial expression and the great feeling she can give to people."

Singer Lin, who is being called the "smiling angel", has already become a media celebrity because of her performance.

She told state-run China Daily that she felt "beautiful" in the red dress she wore during the performance.