Fallen cycling hero Lance Armstrong personally apologised on Monday to staff members of the Livestrong cancer charity ahead of his much anticipated interview with talk show diva Oprah Winfrey.
"Lance came to the Livestrong Foundation's headquarters today for a private conversation with our staff and offered a sincere and heartfelt apology for the stress they've endured because of him," Livestrong spokeswoman Rae Bazzarre told AFP.
She added Armstrong - a cancer survivor who founded the charity in 1997 - urged Livestrong staffers "to keep up their great work fighting for people affected by cancer."
Journalists staked out Armstrong's home in Austin earlier Monday ahead of his interview with Winfrey, during which the disgraced cyclist is reportedly planning to admit to doping.
For years he has repeatedly denied taking performance enhancing drugs to win the Tour de France and other big cycling events.
Reporters, photographers and TV crews took up positions across the street from Armstrong's opulent Austin home, which is surrounded by a 2.4-metre stone wall.
The interview with Winfrey is scheduled to be taped at Armstrong's home on Monday and is to air on her cable network on Thursday. It will also be streamed on its website.
The announcement Armstrong had agreed to an interview has sparked widespread speculation he might finally confess to being a drug cheat after years of strenuous denials.
According to USA Today, Armstrong plans to confess in the interview to doping throughout his career but will not go into great detail about specific cases and events.
It will be Armstrong's first interview since he was stripped in October of his seven Tour de France titles after the US Anti-Doping Agency (USADA) said he helped orchestrate the most sophisticated doping program in sports history.
Any confession by Armstrong could have legal or financial ramifications, particularly among big-name corporate sponsors such as Nike that had loyally stood by him even as doping allegations grew.
Since the International Cycling Union effectively erased him from the record books, Britain's The Sunday Times has sued Armstrong for more than STG1 million ($A1.54 million) over a libel payment made to him in 2006.
It had paid Armstrong STG300,000 ($A462,100) to settle a libel case after publishing a story suggesting he may have cheated, and now wants that money plus interest and legal costs repaid.
On Sunday, the Sunday Times took out an ad in the Chicago Tribune newspaper setting out 10 questions that Winfrey should ask Armstrong.
A Texas insurance company has also threatened legal action to recoup millions of dollars in bonuses it paid him for multiple Tour victories.
Armstrong's years of dominance in the sport's greatest race raised cycling's profile in the United States to new heights.
It also gave the Texan - diagnosed in 1996 with late-stage testicular cancer that had spread to his brain and lungs - a unique platform to promote cancer awareness and research.The Lance Armstrong Foundation has raised almost $US500 million since its creation in 1997.