Michael Schumacher has signed for the Mercedes-Benz Formula One team, and has already set his sights on challenging for the 2010 world title.
Schumacher's F1 return comes after three years in retirement, having stopped racing in F1 at the end of 2006. He will be 41 in January.
Schumacher said: "The motivation is pretty straightforward. I got a call from Ross (Brawn, team principal) at the beginning of November asking me to race again, telling me Mercedes were going to be involved.
"I've never left the race track, and after three years I regained the energy I'm feeling now. After playing around on motorbikes, I'm ready for the serious stuff."
Germany's Bild newspaper is reporting that he has signed a one-year deal with options for a further two years depending on performance. Schumacher has said he and Mercedes are "talking about a three-year deal."
Schumacher is reported to be earning seven million euros (£6.2m) - a relatively modest salary compared to the sport's highest earners, such as Fernando Alonso and Lewis Hamilton, who reports suggest could be earning two to three times as much.
Last season he came close to a sensational mid-season comeback when he was asked to fill-in for the injured Felipe Massa at Ferrari.
However, those plans were scuppered by a neck injury that he had picked up in a motorcycle crash earlier in the year. He says that injury is no longer a problem.