Cyclist Lance Armstrong (L) addresses participants at The LIVESTRONG Challenge Ride as Doug Ulman (R), Livestrong President and CEO, looks on at Palmer Events Center on October 21, 2012 in Austin, Texas.

Lance Armstrong prepares to take part in the Power of Four mountain bicycle race, Snowmass Village, Colo. Aug. 25, 2012. 

Lance Armstrong finishes the Power of Four Mountain Bike Race on Aspen Mountain on August 25, 2012 in Aspen, Colorado.

Lance Armstrong (L) arrives at the 2012 Vanity Fair Oscar Party hosted by Graydon Carter at Sunset Tower on February 26, 2012 in West Hollywood, California.

Lance Armstrong attends the 2011 Pan-Massachusetts Challenge on Aug. 6, 2011 in Bourne, Mass. (Photo by Gail Oskin/Getty Images)

LIVESTRONG Founder and Chairman and seven-time Tour de France champion Lance Armstrong (L) speaks as American Cancer Society Cancer Action Network Chief Executive John Seffrin (R) listens during a news conference at the National Press Club March 24, 2011 in Washington, DC.

Lance Armstrong of the USA and Team Radio Shack competes during Stage Five of the 2011 Tour Down Under on January 22, 2011 in Adelaide, Australia.

Lance Armstrong of team Radioshack (C) stands on the podium to receive the Team Classification award after the twentieth and final stage of Le Tour de France 2010, from Longjumeau to the Champs-Elysees in Paris on July 25, 2010 in Paris, France.

Former cyclist Lance Armstrong runs on Bedford Avenue in Brooklyn during the ING New York City Marathon November 5, 2006 in New York City. The seven-time Tour de France winner is competing in his first marathon.

Lance Armstrong of the USA riding for the Discovery Channel cycling team in the yellow jersey after stage 21 on the podium of the 92nd Tour de France between Corbeille-Essones and the Champs Elysees in Paris on July 24, 2005 on the Champs Elysees in Paris, France.

Musician Sheryl Crow (L) and Tour De France champion Lance Armstrong arrive at the premiere of Universal's 'Meet the Fockers' at the Universal Amphitheatre on December 16. 2004 in Los Angeles, California.

Lance Armstrong celebrated his historic 6th Tour De France win with a special appearance on the Tonight Show with Jay Leno. As a surprise, the Teutul family of the Discovery's hit show, Orange County Choppers presented Lance with a special, custom-designed chopper to commemorate Lance's accomplishments on the tour September 1, 2004.

Lance Armstrong of the USA riding for the U.S. Postal Service team in the yellow jersey, on the podium after Stage 20 of the Tour de France between Montereau and The Champs Elysees on July 25, 2004 in Paris, France.

Lance Armstrong of the USA riding for the US Postal-Berry Floor team (center) in the Yellow Jersey, on the podium after stage twenty between Ville D'Avray and the Champs-Elysees in Paris, of the Tour de France on July 27, 2003 in France. Armstrong won his fifth consecutive Tour de France title.

Lance Armstrong puts on the yellow jersey after stage 14 of the 2002 Tour De France on July 21th, 2002 in Mont Ventoux, France.

Lance Armstrong during Stage 18 of the Tour de France between Monlucon and St-Armand-Montrond in France, 27th July 2001.

Lance Armstrong of the U.S. Postal Service Team wears the Yellow Jersey of the Leader as he accepts awards before Stage 15, Briancon to Courchevel, France of the Tour de France July 16, 2000.

The 1999 Tour de France winner Lance Armstrong of the USA (centre Yellow jersey), with his US Postal team mates after stage 20 between Arpajon and Paris, France July 23, 1999.

Lance Armstrong gets checked over during the Tour De France in Saint Brieuc, France on June 30, 1995.

Lance Armstrong looks on during the Tour DuPont. in January, 1991.

17-year-old Lance Armstrong competes in the Jeep Triathlon Grand Prix in May 1988 as a professional triathlete.