As turn ups for the books go, they don't come much bigger than this.
Lance Armstrong, the most successful Tour de France rider in history, is coming out of a three-year retirement to compete in arguably the toughest event in sport.
The 36-year-old, who beat testicular cancer before winning an unprecedented seven Tour titles, retired back in 2005 with the world at his feet.
Hob-nobbing with presidents and global leaders and running his own cancer charity have taken up much of his time, but the competitive fires obviously still burn brightly for one of sport's all-time greats.
Armstong - it is difficult to think of a more competitive sportsman - has served warning to his would-be rivals that three years away from the cutting edge of the sport have done nothing to diminish his abilities.
"When Iím on the bike I feel just as good as I did before," he told Vanity Fair.
Armstrong is one of a handful of sporting figures - Pele, Diego Maradona, Muhammad Ali, Michael Schumacher, Usain Bolt, Tiger Woods (fill in your own blanks) - who transcend their sport.
Ask my wife about Eddy Merckx, often regarded as the best cyclist of all time, and you'll get a blank look. Mention Armstrong and you'll get an enthusiastic account of his two best-selling books and a glowing tribute to an inspirational figure.
But his hard-earned reputation is now on the line.
Anything less than an eighth Tour title will surely be seen as a failure. So why do you think Armstrong has done it?
He certainly isn't be the first sportsman to change his mind. Major figures like Michael Jordan, Bjorn Borg and Sugar Ray Leonard have all - with varying degrees of success - come out of retirement for one last crack at glory.
The questions are almost endless. Is Armstrong right or wrong to risk his legacy? Where does it rank amongst the other sporting comebacks in history? What does his return mean for cycling as a sport?
Would you bet against Armstrong winning the Tour again in 2009? And who will he ride for?