Five-time Olympic champion Ian Thorpe has denied using performance-enhancing drugs and promised to clear his name.
The French newspaper L'Equipe revealed that a test before Thorpe's retirement showed unusually high levels of naturally-occurring hormones.
"I have never cheated," said Thorpe, who admitted the existence of the test. "I was in complete shock to hear of this report, I didn't know what to do.
"My accomplishments in this sport in people's eyes are being diminished."
Thorpe continued: "I had no previous knowledge of any result of this kind and I did not understand how a test result that supposedly related to me, which must have been undertaken some time ago given my retirement, could be being leaked to a French newspaper when I did not know about it.
"I have complete confidence that all the evidence will establish that I am clean"
"I can now confirm that a test that was undertaken in May 2006 while I was in Australia returned unusual levels of testosterone and a hormone called leutenising hormone. Both these substances are naturally occurring substances.
"There are many innocent physiological and pathological reasons why a test may return unusual levels of these substances.
"The Australian Sport Anti-Doping Authority (ASADA) were at pains to reassure me that I have not failed a drug test and they made it clear to me that any suggestion that is being made to this effect is just plain wrong.
606: DEBATE
"I have complete confidence that all the medical and scientific evidence will establish that I am clean.
"I have always been, and remain, a strong supporter of the drug testing system. Most people will probably recognise that I have been one of the most tested athletes.
"My reputation as a fair competitor is the most valuable thing that I take out of my time in swimming."