Seven-time Tour de France winner Lance Armstrong admits he is feeling "a heck of a lot of nerves".

He was speaking ahead of his high-profile return to the event this weekend.

American Armstrong retired in 2005 but returned to competitive cycling this season.

He will join Levi Leipheimer and Alberto Contador on the Astana team for the Tour, which begins in Monaco on Saturday, and admits he is feeling the butterflies.

"I don't have the same confidence as I had before, that's natural, I think, after being away for four years," he told Eurosport.

"I come with an extreme sense of excitement and also, quite honestly, a heck of a lot of nerves but come Saturday afternoon I'll be excited to be there. I'm going to race hard for three weeks and if that's for Alberto or Levi or anybody else on the team, the most important thing is we win the race.

"It's just great to be here and be in this great principality. What a beautiful setting and what a great place to start this tour."

Asked whether this is the "first step" of his comeback, Armstrong said: "There's been other days before this one but yes, the tour is the jewel of cycling, the one event people follow in the United States, Asia, eastern Europe or Africa, the one that captures everyone's imagination.

"So of course the impression is that this is the beginning. But there was a lot of hard work that went into it before, not just in racing but in training - a lot of preparation, a lot of thought went into it - but certainly it's the one everyone will pay attention to."