Lance Armstrong apologized to the staff of his cancer foundation Monday and admitted to Oprah Winfrey that he used performance-enhancing drugs, a source told The Associated Press.
"He had a private conversation with the staff, who have done the important work of the foundation for many years," said Livestrong Foundation spokeswoman Katherine McLane.
Armstrong's interview with Winfrey, scheduled to air Thursday, is his first since being stripped of his seven Tour de France titles.
"Armstrong will address the alleged doping scandal, years of accusations of cheating, and charges of lying about the use of performance-enhancing drugs throughout his storied cycling career," according to a news release from Winfrey that called the event a "no-holds-barred interview."
Armstrong has always vehemently denied using performance-enhancing drugs and has never been proven to have tested positive.
But an October report from the U.S. anti-doping body USADA cited Armstrong's involvement in what it characterized as the "most sophisticated, professionalized and successful doping program that sport has ever seen," involving anabolic steroids, human growth hormone, blood transfusions and other doping.
Less than two weeks later, Armstrong's seven Tour de France victories were nullified and he was banned from cycling for life after the International Cycling Union ratified the USADA's sanctions against him.
Armstrong, a survivor of testicular cancer, stepped down as a Livestrong board member in November.
The foundation, originally called the Lance Armstrong Foundation but known informally for years as Livestrong, formally dropped Armstrong's name from its title in October.
Armstrong founded the organization in 1997.