Lance Armstrong, 36, announced he is coming out of retirement and plans to compete in the 2009 Tour de France as a way of raising global awareness in his fight against cancer.

Citing the slow pace of last year’s Tour and the rush from last month’s Leadville 100 race, Armstrong decided it was time to return.

“This kind of obscure bike race, totally kick-started my engine,” he told Vanity Fair in an exclusive interview, referring to the lung-searing 100-mile mountain bike race through the Colorado Rockies. “I’m going to try and win an eighth Tour de France.”

Armstrong said full details of his comeback will be announced Sept. 24 at the Clinton Global Initiative in New York.