Armstrong, 39, quit the sport in 2005 before returning in 2009, but in July he confirmed that 2010 would be the last time he rode the Tour de France. In what is likely to be his last season, The Tour Down Under is the Texan's first confirmed race for 2011.

The Australian event runs from January 16-23 in the state of South Australia. "I'm excited to be competing in my last professional ride outside the U.S. at the Tour Down Under," said Armstrong, who finished 23rd overall in his final Tour de France, 40 minutes behind winner Alberto Contador.

Armstrong chose the 2009 edition of the Tour Down Under to make his comeback to cycling after a two-year retirement and debuted his own professional team, Team Radioshack, in this year's race."It will be my third time to the event and I'm sure I will enjoy it as much as I have the first two times," added Armstrong, who is currently the focus of a federal investigation in the United States into doping in professional cycling.

"I will never forget the reception we received in Adelaide when we kicked off the Livestrong global campaign. I look forward to racing and also checking in on the progress in South Australia."

Cancer survivor Armstrong chose the 2009 Tour Down Under to launch his Livestrong campaign to battle cancer worldwide.