Lance Armstrong is chasing an eighth Tour de France title and an elusive feat: persuading everyone he’s clean.

As Armstrong reunites with his close friend and Astana team director Johan Bruyneel, the man behind his yellow jerseys, he’s also adding a new member to his support group. Anti-doping expert Don Catlin has been hired to test Armstrong anytime, anywhere–and to post the results online for the world to see.

“I think it’s the first time an athlete can actually be totally validated on the chance he’s successful,” Armstrong said yesterday. “In my opinion, Don Catlin is beyond reproach.”

Armstrong disclosed details of his comeback two weeks after saying he would end a three-year retirement. He’ll ride for Astana and will compete in the Tour Down Under in Adelaide, Australia, in January.

The setting was the Clinton Global Initiative, the annual meeting of former President Bill Clinton’s foundation. Armstrong held a news conference to talk cycling after announcing a new worldwide campaign to fight cancer before an audience of political and corporate leaders.

As he described his 2009 Tour plans, the 37-year-old Armstrong sometimes made it sound as though this was more a publicity move to raise awareness about the fight against cancer than a legitimate shot at winning an eighth title.

“I think we’re sure we’ll have success with the movement, because we need it,” he said in an interview with the Associated Press, “but I’m not sure I’ll be the fastest cyclist in the world.”