Kamui Kobayashi will continue as Toyota's test and reserve driver for a second season this year.
The Japanese driver is currently leading the GP2 Asia Series and will also return for a second year of the main GP2 championship with DAMS.
"I'm really pleased to be continuing with the team and I'm looking forward to the challenge of developing the TF109," said Kobayashi. "It will be another busy season for me, but I am young and I love driving racing cars so it's no problem.
"This is an important year for me because I want to enjoy success in GP2 as this is the perfect stepping stone for a career in Formula One. I don't know what the future will hold but I will fight all the way."
Kobayashi says his ambition is to become the first Japanese race winner in Formula One, and hopes to achieve that with Toyota.
"The biggest thing for me is that no Japanese driver has ever been a Formula One winner so that is my ultimate dream. I know it would make the Japanese people incredibly proud if a Japanese driver could win races in a Toyota; that would mean a lot.
"But before thinking about that kind of thing, my priority has to be constantly improving and eventually earning a Formula One race seat."