Student Samuel Koch was trying to jump over a series of moving cars while wearing 'kangaroo' spring stilts when he got caught by the fourth vehicle - driven by his father - and fell. As he lay motionless on the floor, distraught Wetten, dass? host Thomas Gottschalk called for a doctor and the cameras panned away from the stage. The 23-year-old was conscious and treated for a number of minutes before being strapped to a spinal board and taken to hospital.
Last night he was operated on at the University Hospital in Dusseldorf, but there was no news on his condition.
Wetten, dass? (Bet it?) features stunts by members of the public and is one of the most watched shows in Europe.
Koch had claimed he could leap five cars within four minutes in his spring-propelled stilts.
After the accident, TV chiefs showed repeats of musical acts which had previously appeared on the show for 25 minutes before finally cancelling the programme.
Take That and American teenage star Justin Bieber had been due to perform.
Gottschalk announced:'We will here and now break off the programme. Anything else would be wrong. We feel responsible to not make jolly when we are not.'
When he had introduced the stunt, Gottschalk told the audience that he had been very worried watching rehearsals of Koch jumping over cars being driven towards him.
He had told magazine Der Spiegel: 'I have never been so scared that something would happen to this young man. I can only say, I hope all goes well.'
The magazine speculated that the stunts were becoming increasingly dangerous at least in part due to competition from the rival Das Supertalent show which goes out on a rival station at the same time.
Koch was jumping over successively bigger cars, and broke off the second jump, looking irritated and stressed, according to Der Spiegel.
He cleared the third but the fourth, which was being driven by his father, was too much and he caught himself on it somehow and crashed to the floor.
It is the first time in 29 years that the show has been cancelled.
Gottschalk said later:'It is the first time in my long, long career that such a thing has happened and we have carried out many dangerous stunts.
'I have always said that would be the worst thing for me, if something happened to one of my candidates in a live show. I regret enormously that this has now happened.'