David Millar admits he will be nervous when he makes his competitive return to cycling after his two-year doping ban in the Tour de France on Saturday.
The 29-year-old Scot's suspension only ended last Friday but he will be one of the favourites for the 7.1km prologue.
"I'm a little bit apprehensive," he said on Thursday. "I had a lot of respect from the professional peloton before, but now I have to earn it.
"If anything, I'm ashamed more than anything else."
Millar has three stage wins to his name and held the yellow jersey for three days at the start of the 2000 Tour.
He and Gilberto Simoni, the 34-year-old Italian who finishing third in the Giro d'Italia last month, will carry the hopes of the Saunier Duval team.
Millar admitted it was while watching the Tour de France last year, during his ban, that he realised exactly what he had ruined.
"It was like seeing it from the eyes of a child," he said. "That's when I realised the opportunity I'd had and how I wasted it.
"It was horrible, but that is to be expected. That is part of the punishment. "But sometimes you have to hit rock bottom to then realise what you have got."