Transcript for 'The Armstrong Lie' Details Cycling Champ's Web of Deceit
You're inside one of the most challenging sporting events on earth with access no outsider -- ever had to Lance Armstrong. At the time still considered a seven time winner. But what Academy Award winning filmmaker Alex did he and his studio didn't know despite a year in -- Lance Armstrong's normally private bubble. Was that it was all a lie and they too were being played a lot of people wonder why would Lance talk to you. I think that particularly at the beginning there was a sense of invulnerability the sense that. Nobody is ever gonna discover my -- so come along for the ride. The ride ended up traversing Armstrong's epic collapse leaving give -- with moments he never imagined capturing. I certainly was very confident that I would never be -- A shell shocked Lance Armstrong matter of factly explaining how it all began. His decision to cheat by using performance enhancing drugs. -- was a group of us primarily live in and Italy and we just said we either have to play ball here are gone. We just thought that -- had it was just happens at noon hour. The latter. But but but but but. -- maybe. Maybe -- that approach the decision differently today but at the time I didn't lose sleep over. It is a slice of the new film the Armstrong -- Which dissect what's been called the biggest fraud in all of sports and explores how -- life became so all consuming Armstrong would -- almost any. Need to be protected I had never -- -- have never taken performs in his my best defenses I've never tested positive how do you rate Lance is a liar. And even more than that as a copper up artist he is. -- tippy top he's one of the very best. The Armstrong -- is a film it never intended to me. He was directing a feel good story about Armstrong's 2009 comeback. They finished it complete with narration by Matt Damon but before they could release it. On Nightline did Lance. Sheet Nightline ran a tell all former teammate Floyd Landis who dropped -- bomb. Did you see Lance Armstrong receiving transfusions -- more than -- I guess multiple times. Look at some point people have to tell -- kids Santa Claus isn't real. I hate to be do it by. It's just not real. They put the film on the shelf and re shot a completely different story it was Lance is abuse of power. That is really the more reprehensible -- part of that was the way he went after people -- was -- way he actually wrapped himself in the -- Of the cancer survivor he first confessed to Oprah. Did you ever take banned substances to enhance your cycling performance yes. Did you ever blood dope or use blood transfusions to enhance -- cycling performance yes. And all seven of your Tour de France victories did you ever take banned substances or plateau just. Armstrong talked to give me. Hours later limit alive. I didn't live. A lot of allies -- -- -- the -- and and it's different. I guess it's time. Photos from behind the scenes with -- -- show -- fallen champion who has lost some of his swagger still Armstrong trusted give me from their earlier time together and for the first time. Agreed to explain some of these secrets including how he got away with using the blood booster EPO. The half -- -- EPO is. Four hours. So. You can back it up from there and figure out. And when you're in trouble. When he passed every test because he does not -- -- BO. Jesse will -- my defense was that I have passed server control you've given and that's true the samples that were given work clean. Much of Armstrong's life today centers around trying to keep what he has left. Three major lawsuits including a fraud case brought by the US Department of Justice they seek to strip him of more than 100. Million dollars. You talk to anymore the last time like communicated with Lance was when I let him know the -- The -- going to be called the Armstrong -- Product or not so well if his reputation stands a chance that any kind of redemption. It will likely take awhile. People don't like that troops as much as they liked the beautiful -- And that's a hard thing for -- to accept because he found much more affection. Beautiful mind and the ugly truth. And Neal Karlinsky for Nightline in Los Angeles.
This transcript has been automatically generated and may not be 100% accurate.