A photo of an unidentified flying object high in the Belgian sky has been puzzling NASA scientists for over two decades.

But the mystery has now been solved: the man who took the shot has spoken out, and admitted the contraption was a fake he made from polystyrene.

Debunked: This photo, supposedly of a UFO over Belgium, has puzzled experts since 1990.

The picture shows a triangular-shaped flying saucer with four lights, allegedly photographed in April 1990 by a young worker. The photo was released after several sightings of UFOs over Belgium in 1989 and 1990.

Then aged 18, the man identified only as Patrick said he'd decided it was time to come clean.