Lance Armstrong confessed to American television personality Oprah Winfrey that he used performance-enhancing drugs to win the Tour de France in an interview on Monday, according to a person familiar with the situation.
The person spoke on condition of anonymity because the interview is to be broadcast Thursday on Winfrey's network.
After more than a decade of denying that he doped to win the Tour de France seven times, Armstrong sat down in a 90-minute, question-and-answer session with Winfrey.
The interview is Armstrong's first public response to a 1000-page US Anti Doping Agency report that portrayed him as a ruthless competitor, willing to go to any lengths to win the prestigious race.
Armstrong was stripped of all seven Tour titles last year following the report.
Prior to the interview Armstrong on Monday visited his Livestrong cancer foundation where he apologized to staff there.
(Read More: Lance Armstrong's Livestrong in Jeopardy? )
The Winfrey interview and Armstrong's anticipated confession has transformed Armstrong's quiet upscale neighborhood into a destination for media awaiting word of an apology and for onlookers snapping souvenir photos.
But Armstrong managed to slip away for a jog and it was during this time that an Associated Press Sports Writer, Jim Vertuno, spotted him along the road, pulling alongside him for a chat on Sunday.
"He was quite relaxed, told me he was calm and at ease and ready to speak candidly with Oprah Winfrey today," Vertuno said.
"He would not divulge what he was going to say to her today. It's anticipated, it's expected he will make some sort of limited confession and apology related to the doping charges against him - allegations he's denied for over a decade. It's a big moment for him," Vertuno said.