The bike was later seized after she had withdrawn from the race on Saturday with a mechanical problem.
"It wasn't my bike, it was my friend's and was identical to mine," Van den Driessche told Belgian TV channel Sporza.
"This friend went around the course Saturday before dropping off the bike in the truck. A mechanic, thinking it was my bike, cleaned it and prepared it for my race."
Van den Driessche said she feared her career could now be over but she still hoped for a second chance and was not afraid of any investiagtions into the case.
"I'm aware I have a big problem. I have done nothing wrong," she said.
In a sport that has long battled with a major doping problem, suggestions and rumours of 'motorised doping' have long floated around too, but nothing has been proved in major competition until this case.
It prompted Cookson, who confirmed the case would be investiaged by the UCI's disciplinary commission, to say:
"We've heard some stories for a long time now about the possibility of this.
"We have been alive to a potential way that people might cheat and we have been testing a number of bikes and a number of events for several months.
"I am committed and the UCI is committed to protecting the riders who do not want to cheat in whatever form and to make sure that the right riders win the race."
-AAP