Williams has confirmed it will retain Felipe Massa and Valtteri Bottas as its drivers for the 2015 Formula One season.

Massa was already under contract but on Sunday the team announced it has taken up the option on Bottas' contract following an impressive campaign.

Team principal Frank Williams says "Felipe is a pleasure to work with, and combines raw pace with a wealth of experience. As for Valtteri, we have known for many years he is a very special talent."

Massa joined Williams following his release from Ferrari at the end of last season and secured the team's first pole position since 2012 at the Austrian Grand Prix.

Bottas has secured four podiums in the last five races to lie fifth in the drivers' standings.