Docu-maker on Lance Armstrong: 'He goes into lying mode'
16 October 2013 Last updated at 12:41 BST
The Oscar-winning documentary maker Alex Gibney set out to make a feel good film about the comeback of cyclist Lance Armstrong, following him through the 2009 Tour De France.
Shortly before the film was due to be released, the cyclist became the subject of a Federal investigation, followed by revelations he had been using performance-enhancing drugs.
Gibney decided to use his access to the man at the centre of one of sport's biggest ever cover-ups to make a film about the "lie".
"When I looked back at the footage... I realised there were a lot of moments where he was lying to me, straight to my face."