Tyler Hamilton hopes Lance Armstrong will "come clean and tell the truth" - for himself and for the sport of cycling.
Hamilton was one of 11 of Armstrong's former team-mates who have testified against him to the United States Anti-Doping Agency (USADA), which has released the reasons behind its decision to strip him of his seven Tour de France titles and hand him a lifetime ban.
"We all have told the truth for different reasons," Hamilton told BBC Radio 5 Live. "Maybe someday Lance Armstrong will be comfortable enough to come clean and tell the truth."
He added: "The evidence is out there. Lance and I were team-mates for four years. I saw it. We doped together.
"Hopefully he'll just come out with the truth. I think it'll be better for the sport and actually better for him."
USADA chief executive Travis T Tygart, said there was "conclusive and undeniable proof" of a team-run doping conspiracy at Armstrong's US Postal Service Pro Cycling Team.
Armstrong decided earlier this year not to fight the USADA charges, but has always denied any involvement with doping.
Hamilton won a time trial gold at the 2004 Olympics, but later was twice handed doping bans. In 2011 he admitted to using banned substances in competition and was formally stripped of his Olympic medal the following year.
Hamilton said he and his team-mates were given the tools to keep one step ahead of the anti-doping testers.
"Looking back I wish the tests were better back then," he said. "We had sophisticated doctors, working for the riders. Our doctors were always one if not two steps ahead of the drug testing. They knew how to beat them."