Beijing - The 200 female guides who led each country's athletes onto the National Stadium during last week's opening ceremony of the 2008 Olympic Games had to strip naked to qualify for the job, a local media report said Friday.

Thousands of young ladies from colleges and dance academies in Beijing competed for the chance to appear before a huge worldwide audience.

During the selection process, the women were required to strip so teachers judging whether they were qualified could measure their body proportions, The Beijing News said.

In an interview with one of the girls who competed for the high profile job, the 20-year-old college student Zhang Fan told the paper that the girls were put in a room and teachers measured them with a ruler.

No specifics were given but the measurements were called "bone measurements" which typically include measuring the width of shoulders and waists, length of waists and height.

The women had to be at least 1.66 metres tall, have a pretty face and possess youthful energy, the report said.

Zhang did not qualify but she was later selected to be one of the 400 cheerleaders on the stadium who were the longest performers during the three-and-a-half-hour long extravaganza on August 8.

Dressed in short white dresses, boots and caps, the women had to constantly dance and cheer, to create a good atmosphere and rouse the audience of 91,000 people at the stadium.

The 400 women also performed the smiling programme - in which they danced and opened umbrellas each with a smiling face on them.

For that three-minute performance, the women had to undergo half a year of training, rising every day at 5 am to get to the practice site by 6 am and returning to their school dormitory as late as 8 or 9 pm, Zhang said. Sometimes when the training starts at noon, the women would practice till 1 am or 2 am.

They practiced standing in a row at different positions on the stadium, and also rehearsed dance movements and the opening and closing of umbrellas - a simple task which each women had to practise doing for more than 1,000 times, the report said.

Zhang said she smiled so much during practice that her facial muscles stiffened, but she was glad to have been selected.

Details about how China put together the spectacular opening ceremony are slowly being revealed - including revelations that were controversial.

After the ceremony, organizers admitted that most of the fireworks display shown on television were actually not the fireworks set off that evening, but were recorded in advance.

They also said a girl whose song during the ceremony won wide praise did not actually appear in the stadium and her song was mimed by another girl who was considered more attractive to foreign audiences.

And on Friday, state media said the nearly 900 soldiers operating the huge scroll that formed the centrepiece of last week's show had to stay hidden under the structure for up to seven hours, wearing nappies because they were not allowed toilet breaks.

Almost one third of the world's population - a little over 2 billion people - watched the ceremony, according to the global market research company Nielsen on Thursday. (dpa)