Montreux - China's swimming star Sun Yang, accused of smashing a blood vial with a hammer, faces an eight-year ban if charges against him are upheld by the Court of Arbitration for Sport on Friday.
Triple Olympic champion Sun, winner of 11 world titles and a national hero back home, will appear in person at the hearing in a bid to clear his name of allegations he missed an out-of-competition doping test in September last year.
FINA, the international swimming federation, confirmed in January that the swimmer had used a hammer to smash a vial containing his own blood sample.
But the federation sided with the swimmer and cleared him of wrongdoing, finding that testers had failed to produce adequate identification or follow correct protocol during the procedure.
The ruling outraged the World Anti-Doping Agency (WADA) who took the matter to CAS demanding a ban of between two and eight years for Sun, who served a doping suspension in 2014, for missing the out-of-competition test.
Sun "will be present" at Friday's CAS hearing and "is expected to testify," CAS secretary Matthieu Reeb told AFP.
After being cleared by FINA Sun was able to compete in the World Championships in Gwangju, South Korea, in July, where he won two golds but became a focus of protests from rivals.
Australian Mack Horton refused to share the podium with Sun after coming second to him in the 400m freestyle. Horton received an ovation from fellow swimmers at the athletes' dining hall for his protest.
The court proceedings have been moved from the CAS headquarters in Lausanne to Montreux to cope with an expected high influx of media and will for only the second time in the tribunal's history be conducted in public.
Proceedings will be live-streamed on the CAS website.
The first hearing in public, in 1999, also involved FINA, which had found Irish swimmer Michelle Smith De Bruin guilty of doping. Smith requested an open hearing. CAS ruled for FINA, who had found that Smith had tried to dilute her urine sample with alcohol.
The request for a public hearing this time came from Sun, who has battled to clear his name since the scandal blew up.
"Public opinion, badly informed, has twisted the facts," Sun said recently on social media.
CAS said a ruling will not be issued Thursday but at a later date following court deliberations.