Lance Armstrong confessed to Oprah Winfrey during an interview Monday that he used performance-enhancing drugs to win the Tour de France, a person familiar with the situation confirmed to NBC News.
The person spoke on condition of anonymity because the interview is to be broadcast in two parts Thursday and Friday on Winfrey's network.
"Emotional doesn't begin to describe the intensity or the difficulty I think he experienced in talking about some of these things," Oprah told CBS' "This Morning" on Tuesday, saying she and others in the room were "mesmerized and riveted" by what he said.
She told CBS that during a grueling two and a half hour interview, Armstrong was thoughtful and serious in the way he answered her questions, and she said she was satisfied.
"I went in prepared to have to dig and pull and reference," Oprah said. "I didn't have to do that because he was so forthcoming."
Oprah said she wasn't sure why Armstrong decided to come clean about his doping when he did. "I think he was just ready," she said.
Armstrong was stripped of all seven Tour titles last year following a voluminous U.S. Anti-Doping Agency report that portrayed him as a ruthless competitor, willing to go to any lengths to win the prestigious race.
USADA chief executive Travis Tygart labeled the doping regimen allegedly carried out by the U.S. Postal Service team that Armstrong once led, "The most sophisticated, professionalized and successful doping program that sport has ever seen."
After a federal investigation of the cyclist was dropped without charges being brought last year, USADA stepped in with an investigation of its own. The agency deposed 11 former teammates and accused Armstrong of masterminding a complex and brazen drug program that included steroids, blood boosters and a range of other performance-enhancers.
A group of about 10 close friends and advisers to Armstrong left a downtown Austin hotel about three hours after they arrived Monday afternoon for the taping. Among them were Armstrong attorneys Tim Herman and Sean Breen, along with Bill Stapleton, Armstrong's longtime agent, manager and business partner. All declined comment entering and exiting the session.
Soon afterward, Winfrey tweeted: "Just wrapped with (at)lancearmstrong More than 2 1/2 hours. He came READY!" She was scheduled to appear on "CBS This Morning" on Tuesday to discuss the interview.
In a text to the AP on Saturday, Armstrong said: "I told her (Winfrey) to go wherever she wants and I'll answer the questions directly, honestly and candidly. That's all I can say."
Armstrong stopped at the Livestrong Foundation, which he founded, on his way to the interview and said, "I'm sorry" to staff members, some of whom broke down in tears. A person with knowledge of that session said Armstrong choked up and several employees cried during the session.
The person also said Armstrong apologized for letting the staff down and putting Livestrong at risk but he did not make a direct confession to using banned drugs. He said he would try to restore the foundation's reputation, and urged the group to continue fighting for the charity's mission of helping cancer patients and their families.
Armstrong spoke to a room full of about 100 staff members for about 20 minutes, expressing regret for everything the controversy has put them through, the person said. He told them how much the foundation means to him and that he considers the people who work there to be like members of his family. None of the people in the room challenged Armstrong over his long denials of doping.
Winfrey and her crew had earlier said they would film Monday's session at Armstrong's home. As a result, local and international news crews were encamped near the cyclist's Spanish-style villa before dawn.
Armstrong still managed to slip away for a run despite the crowds outside his home. He returned by cutting through a neighbor's yard and hopping a fence.