Williams is to retain Felipe Massa and Valtteri Bottas for 2015.

Massa joined the Grove outfit for the start of 2014 and secured the team's first pole position since 2012 at the Austrian Grand Prix. A proven race winner with 11 wins and 36 podiums to his name, he competed in his 200th Grand Prix at Silverstone in July and next year will be his 14th season in Formula One.

Valtteri Bottas joined Williams in 2010 as a Test Driver and graduated to a race seat in 2013. He has secured four podium finishes so far this season and has matured into one of the sport's most promising young talents, currently sitting fifth in the Drivers' Championship.

Both drivers have proved crucial in the development of the Williams FW36 and the team is confident that it has one of the strongest driver pairings on the grid. Williams will be announcing its test and development driver roles for 2015 in due course.

"I'm really enjoying my time at Williams and I feel settled here," said Massa. "Williams is such an iconic name in motor racing and I have a lot of pride when racing for this team. This season we have started to show our true potential and I'm driving a car that is looking strong and has improved a lot as the season has progressed which is very encouraging for the future. It's important that we continue to push in the second half of the season and that we start 2015 with some really good momentum that we can build on."

"I've been a member of the Williams team for five years now and we have developed together throughout that time which is a great feeling," added Bottas. "The team has also made some very impressive gains this season and I'm confident that I'm at a team that is moving in the right direction and can continue to be competitive. Sir Frank and Claire have put a lot of faith in me and I'm very grateful that they continue to do so. Felipe and I have a good working relationship and this early announcement will help us both input into the ongoing development of the FW36 and the FW37."

"I'm delighted to confirm that Felipe and Valtteri will be racing for Williams once again in 2015," said Frank Williams. "Felipe is a pleasure to work with and combines raw pace with a wealth of experience. We have known for many years that Valtteri is a very special talent and in the FW36 we have given him a car that is allowing him to demonstrate his skills. The team is having a much improved 2014 season and the skill of our drivers and their feedback to our engineers has proved crucial in this. This announcement gives us excellent stability for 2015, but of course we are very much focusing our attention on maximising the full potential of the FW36 in the remaining seven races of this season."