"As the ceremony got under way with a dramatic, drummed countdown, viewers watching at home and on giant screens inside the Bird's Nest National Stadium watched as a series of giant footprints outlined in fireworks processed gloriously above the city from Tiananmen Square.
What they did not realise was that what they were watching was in fact computer graphics, meticulously created over a period of months and inserted into the coverage electronically at exactly the right moment.
The fireworks were there for real, outside the stadium. But those responsible for filming the extravaganza decided in advance it would be impossible to capture all 29 footprints from the air.
As a result, only the last, visible from the camera stands inside the Bird's Nest was captured on film.
The trick was revealed in a local Chinese newspaper, the Beijing Times, at the weekend.
Gao Xiaolong, head of the visual effects team for the ceremony, said it had taken almost a year to create the 55-second sequence. Meticulous efforts were made to ensure the sequence was as unnoticeable as possible: they sought advice from the Beijing meteorological office as to how to recreate the hazy effects of Beijing's smog at night, and inserted a slight camera shake effect to simulate the idea that it was filmed from a helicopter."