The sportsman's doping scandal has already cost him his seven Tour de France titles, and now Olympics bosses have stripped him of the bronze medal he won at the Sydney Games in 2000.
Members of the International Olympic Committee (Ioc) sent a letter to Armstrong on Wednesday (16Jan13) ordering him to return the prize.
An Ioc spokesman says, "We have written to Armstrong asking him to return the medal. It was a decision taken in principle at the executive board (meeting) before Christmas."
The news emerged just hours before Armstrong's highly-publicised interview with Winfrey is due to be broadcast in America on Thursday night (17Jan13).
During the Tv special, Armstrong reportedly admits to using performance-enhancing drugs throughout his highly-successful sporting career, but Winfrey has revealed he "did not come clean in the manner I expected".
The cyclist has remained tight-lipped about his rumoured confession, telling the Associated Press, "I left it all on the table with her (Winfrey) and when it airs the people can decide."