Whistleblower Grigory Rodchenkov will testify at the Court of Arbitration for Sport (CAS) hearing of 42 Russians, who are appealing against Olympic bans, via video link.
Rodchenkov's lawyer Jim Walden confirmed the news that his client will be testifying at the hearing, scheduled to take place from January 22 to 28, to German media outlet Frankfurter Allgemeine Zeitung.
"Yes, he will testify but from a distance," he said.
There had been rumours that the former head of the Moscow Anti-Doping Laboratory would be appearing at CAS, with Russian cross-country skier Nikita Kryukov claiming that he had heard the news at the International Olympic Committee’s (IOC) Disciplinary Commission hearing in Lausanne in December.
However, this is the first time that somebody from Rodchenkov's entourage has confirmed the news.
In November, the IOC Disciplinary Commission, led by Swiss lawyer Denis Oswald, declared that Rodchenkov, who is currently under a witness protection programme in the United States, was a credible witness, clearing the way for him to testify.
CAS recently confirmed that 42 of the 43 sanctioned Russian athletes had filed appeals against their lifetime bans from the Olympic Games by the IOC and retrospective disqualification from Sochi 2014.
They were all sanctioned for their involvement in doping and sample tampering at their home Games.
The remaining athlete is bobsledder Maxim Belugin, who it is claimed tested positively for steroids supposedly present in the "Duchess cocktail".
As reported by insidethegames yesterday, Belugin's disqualification was announced by the IOC with the code "SRT-01" while all others have begun "SML", meaning Belugin's case is different from the other 42 Russians disqualified from Sochi 2014.
It appears possible that "SRT" stands for "Sochi re-test" while "SML" refers to "Sochi McLaren" - referencing the McLaren Report which outlined Russian doping offences.
The athletes were among 46 initially investigated by the Oswald Commission.
Three athletes - Olympic figure skating champion Adelina Sotnikova, ice hockey player Anna Shokhina and speed skater Denis Yuskov - were cleared of wrongdoing.
The CAS hearing has been given priority in order for it to finish before the 2018 Winter Olympics in Pyeongchang, South Korea, taking place from February 9 to 25.