American singer Sheryl Crow has reportedly been accused of knowing all about Lance Armstrong's doping during their three-year relationship.

The 50-year-old, who dated the disgraced cyclist a decade ago, is thought to have known that the 41-year-old took performance-enhancing drugs throughout his career.

The Texan admitted to his doping past during an interview with Oprah Winfrey and now his ex-girlfriend has spoken out about the controversy.

"To carry around a weight like that would be devastating in the long run," Crow reportedly said in an interview on Entertainment Tonight.

Once the revelations came to light from the United States Anti-Doping Agency, Armstrong was stripped of his seven Tour de France titles and issued with a lifetime ban from cycling.