Mercedes have confirmed Nico Rosberg has signed a "multi-year contract extension" with the Silver Arrows.
The German currently tops the standings from team-mate Lewis Hamilton heading into his home grand prix at Hockenheim.
"It has been a difficult road to get to where we are now, but everybody kept believing and, thanks to the fantastic support from Mercedes-Benz, we are now leading the way in F1," said Rosberg.
BBC Sport revealed in May that Rosberg, 29, had signed a new deal.
|Andrew Benson, chief F1 writer|
|"Lewis Hamilton and Nico Rosberg make the perfect driver combination for Mercedes. In Hamilton, they have the mercurial superstar, arguably the fastest driver in the world who opens the Mercedes brand out into markets it has sometimes struggled to reach. Rosberg is the perfect foil. He is not quite as out-and-out fast but can do more or less the same job through intelligence and application. Importantly for Mercedes, he is also German."|
The former Williams driver joined Mercedes in 2010 and has taken six victories, 17 podiums and eight pole positions with the Silver Arrows.
He has won three times in 2014 and leads the championship by four points ahead of this weekend's German Grand Prix.
Toto Wolff, head of Mercedes-Benz Motorsport, described Rosberg as one of the best drivers in F1.
He added: "His speed, commitment and focus have all helped to give clear direction and to drive the team forward."
Rosberg, who made his F1 debut with Williams in 2006, added: "We have an awesome team and I am confident that we have the right people in place at every level.
"I'm looking forward to the next years together, when we will keep pushing to win even more races and, hopefully, championships."