A new book claims singer Sheryl Crow told the feds about ex-fiance Lance Armstrong's illegal doping practices. 

"The New York Daily News" reports that in the book "Wheelmen," the authors reveal that Sheryl Crow had witnessed her one-time boyfriend Lance Armstrong receive an illicit blood transfusion in 2004 and later detailed the account to federal investigators. 

Crow then reportedly received immunity from criminal prosecution for her confession. 

"Wheelmen: Lance Armstrong, the Tour de France and the Greatest Sports Conspiracy Ever" by Wall Street Journal reporters Reed Albergotti and Vanessa O'Connell hits shelves next Tuesday.