Sheryl Crow

Lance Armstrong was a revered Tour de France-winning cyclist until he confessed to using performance-enhancing drugs. Now, according to a new book, it's revealed that ex-girlfriend, Sheryl Crow, reportedly witnessed his cheating.

In "Wheelmen: Lance Armstrong, the Tour de France and the Greatest Sports Conspiracy Ever," by Wall Street Journal reporters Reed Albergotti and Vanessa O’Connell, the authors write how the 51-year-old singer witnessed Armstrong receiving an illegal blood transfusion. 

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"Rather than try to hide the transfusion from her, Armstrong was completely open about it," it reads, as reported by "He trusted that Crow would have no desire to tell the press or anyone else about the team’s doping program. He explained that it was simply part of the sport -- that all cyclists were doing the same thing."

The couple broke up in 2006, but a report from Deadspin notes that Crow was contacted by investigators as a grand jury considered a federal indictment against Armstrong. Meanwhile, the New York Daily News reports that she was interviewed as part of the doping investigation in 2011.

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Crow was originally subpoenaed to testify, but the new book claims that she was given a written agreement protecting her from prosecution if she revealed everything she knew about his situation. While she reportedly told investigators what she knew about him, the grand jury eventually dropped the case against Armstrong.

In September, the cyclist returned his Olympic bronze cycling medal, which he won at the 2000 Summer Olympics in Sydney.

Wheelmen: Lance Armstrong, the Tour de France and the Greatest Sports Conspiracy Ever will be available Oct. 15.