Landis says he is confident his name will be cleared

The American tested positive for high levels of testosterone but has always vehemently denied any wrongdoing.

French anti-doping experts have begun analysing his B sample, and he faces a US anti-doping hearing on 14 May.

Landis will participate in road and mountain bike stages of the Ultimate Mountain Challenge on 2-3 June.

The event is a fundraiser for cancer research, and will mark his return to the saddle after a hip replacement operation last September.

Landis said on his website: "I am excited to put my new hip to the test racing in the Rockies.

"This is a wonderful opportunity to raise money for the Prostate Cancer Foundation at the same time."

Landis also plans to compete in Colorado's Leadville Trail 100, a 100-mile (160km) mountain bike race in August.

After his amazing stage 17 win in last year's Tour, Landis' urine sample was found to contain elevated testosterone levels.

The 31-year-old faces a two-year ban and would be the first Tour rider to be stripped of the title if the doping allegations are upheld.