Sheryl Crow told federal investigators she witnessed Lance Armstrong blood doping in 2004, according to MSN.com.

In the book "Wheelmen," due out Tuesday, Wall Street Journal reporters Reed Albergotti and Vanessa O'Connell wrote that the singer supposedly saw then-boyfriend Lance Armstrong get a blood transfusion on his private jet.

That's incredible. I mean, who's ever heard of such a thing ... a guy who rides bicycles for a living can afford his own jet?

"He explained that it was simply part of the sport -- that all cyclists were doing the same thing," the reporters write, adding that now-disgraced Armstrong didn't believe Crow would ever share his secret.

Lance Armstrong and Sheryl Crow arrive at the 2005 American Music Awards at the Shrine Auditorium in Los Angeles, California, Tuesday, November 22, 2005.
Lance Armstrong and Sheryl Crow arrive at the 2005 American Music Awards at the Shrine Auditorium in Los Angeles, California, Tuesday, November 22, 2005. (Lionel Hahn/ABACA Press )

Apparently, when federal agents approached Crow in 2011, she was reportedly offered a deal to avoid prosecution by telling what she'd seen. The Washington Post reported that, according to the book, Crow then told a Food and Drug Administration investigator that she'd seen her ex receiving the illegal transfusion.

Contact Tony Hicks at Facebook.com/BayAreaNewsGroup.TonyHicks or Twitter.com/insertfoot.