For the first time in the history of Formula One, six world champions will be on the grid when the new season starts on Sunday.

Here is a brief look at them (with age, nationality, manufacturer, number of championships, race wins and pole positions):

Sebastian Vettel, 24, Germany, Red Bull

Two-time defending F1 champion

Race Wins: 21

Pole Positions: 30

Is there anything or anyone to stop Sebastian Vettel from joining F1 greats Juan Manuel Fangio and Michael Schumacher as the only drivers to win three consecutive Formula One titles? With his Red Bull car already looking like the preseason favorite, probably not.

Vettel’s ability to push his Austrian team’s car to its capabilities saw the German driver crush the competition and dominate the championship, winning his second straight F1 title with four races to spare.

Vettel, nicknamed “Baby Schumacher,” has shown an ability to tune out the pressure and focus his attention on track, where he made fewer mistakes with a more reliable car than in his first championship-winning season.

His fun, down-to-earth personality also sets him apart from the calculating and businesslike demeanor of fellow German Schumacher.

Jenson Button, 32, Britain, McLaren

2009 Champion

Race Wins: 12

Pole Positions: 7

Button drove with chilling consistency in the second half of last season, getting a podium position in eight of the last nine races, having missed out on the podium in six of the first 10.

He won three GPs and finished in second place overall behind Sebastian Vettel, but also three places above McLaren’s designated No. 1, his teammate Lewis Hamilton.

This will be Button’s third season with McLaren and if he continues to blossom, he will be a candidate to win the F1 championship for the second time.

While Hamilton may have more speed, the experienced Button, with more than 200 GPs to his name, is a master at handling changing weather conditions. He proved that by beating Vettel in the rain in Canada.

Lewis Hamilton, 27, Britain, McLaren

2008 Champion

Race Wins: 17

Pole Positions: 19

For Hamilton, last season was a mixture of off-track distractions, unsavory clashes with Ferrari’s Felipe Massa, and sometimes quite brilliant, if somewhat risky, driving.

The Briton won three races – the most impressive when he tactically outwitted Sebastian Vettel to beat the German in China, yet he also retired from three GPs and finished a disappointing fifth overall. He also finished behind his McLaren teammate Jenson Button, the first time he has lost out to a teammate in his F1 career.

Hamilton’s driving ability rivals anyone’s, but the 2008 champion needs a clearer head this year, and to sort out his contract situation with McLaren as quickly as possible.

Kimi Raikkonen, 32, Finland, Lotus

2007 Champion

Race Wins: 18

Pole Positions: 16

Raikkonen expects to pick up where he left off when he returns to Formula One, despite three years away from the grid. The Finnish driver, who won the 2007 championship title when driving for Ferrari but quit in 2009 and switched to rally and briefly dabbled in NASCAR racing, will make a comeback this season with the Lotus Renault team. “Before my two years of rallying I had nine seasons, 157 races and 18 wins in Formula One,” he said. “When I went to rallying and when I tried NASCAR, there were many new things to learn, but with Formula One I feel like I’m coming home.”

He geared up for the Australian Grand Prix with the best time in last weekend’s final test session. He looks certain to add to the 62 career podiums he has already garnered.

Fernando Alonso, 30, Spain, Ferrari

2005, ‘06 Champion

Race Wins: 27

Pole Positions: 20

Despite two roller coaster seasons, Fernando Alonso still believes Ferrari is capable of providing the Spanish driver with a championship-winning car.

The two-time world champion from Asturias lost the 2010 title to Sebastian Vettel in the last race, three years after losing a chance at the championship because of in-team squabbles with McLaren teammate Lewis Hamilton.

But Ferrari is centered on Alonso, who continues to be rated as the best driver on the grid despite his failure to win a title since leaving Renault. Unfortunately, the Italian team has struggled in preseason.

Alonso has remained cautious, and if Ferrari can find the necessary boost, you can never rule the 30-year-old out of the title race.

Michael Schumacher, 43, Germany, Mercedes

1994, ‘95, 2000, ‘01, ‘02, ‘03, ‘04 Champion

Race Wins: 91

Pole Positions: 68

Michael Schumacher’s decision to come out of retirement after three years went flat soon into the record seven-time world champion’s first season two years ago.

Unfortunately, Mercedes hasn’t provided the car to turn that around to date.

The 43-year-old winner of a record 91 races will persevere with a flicker of hope that team principal Ross Brawn can put together a championship winner, although the Silver Arrows seem to have a lot of catching up to do already.

Schumacher will probably be pleased with a podium at this point - ambition that falls well short of his normal expectations. Schumacher is in the last year of his contract with his future still uncertain.

Schumacher joined Mercedes after the German manufacturer bought out Brawn, F1's then-reigning constructors' champion. He was reunited with Ross Brawn, his technical director at Ferrari where he won five of his titles, and was joined by promising German driver Nico Rosberg.