Kamui, 21, has been associated with Toyota since 2001, and he first raced single-seaters in the Esso Formula Toyota Championship in Japan in 2002.
The TDP scheme, run by Toyota Motor Corporation, is designed to help young drivers achieve their ambitions to compete at the top in motorsport and Kamui’s new role comes soon after news of fellow TDP member Kazuki Nakajima’s 2008 race drive with Williams.
Panasonic Toyota Racing Chairman and Team Principal Tadashi Yamashina said: "I am very pleased to welcome Kamui to the team. He tested the car last winter and showed he had the potential to drive in Formula 1 in the future. Now, after another season gaining experience in Formula 3, we believe he is ready for the challenge of Formula 1. It is also very gratifying to see the TDP scheme delivering results and helping a promising young driver to reach Formula 1."
Kamui has progressed through the single-seater ranks in Europe after making a name for himself in Japanese junior racing.
With TDP support, Kamui moved to Europe in 2004 and spent two years in the Formula Renault Eurocup and Italian Formula Renault Championship, winning both crowns in 2005 - a title double only achieved previously by one other driver.
From there he stepped up to Formula 3, the traditional breeding ground for future Formula 1 stars, and in his two seasons in the Euro Series he proved to be a formidable competitor, showing all the speed and commitment necessary to become the new Panasonic Toyota Racing third driver.
Kamui said: "The TDP scheme has been very supportive of me during my career and I am very grateful for all that support.
"This is a great challenge for me and I am very excited about becoming a Formula 1 driver. Since the start of my career I have dreamed of reaching Formula 1 and to have the chance to join Panasonic Toyota Racing as third driver is a fantastic opportunity for me.
"My first tests for the team last winter went well but I still have things to learn about Formula 1 and it will be a great experience for me to test more regularly for the team.
"The role of third driver is very important as I will be helping a lot with the development of the car throughout the year. I am sure I will learn a lot about Formula 1 cars and hopefully this will help me in my future career but for now I am focused on helping the team move forward."
Kamui Kobayashi Profile
Born: 13 September 1986 - Hyogo, Japan
Marital status: Single
Hobbies.: Music and karate
1996: SL Takarazuka Tournament, Cadet Class: 3rd
1997: SL All Japan Cadet Class: 1st
1998: JAF Cup West Cadet Class: 1st
1999: SL All Japan Tournament (S stock, D class): 1st
2000: All Japan Junior Kart Championship Suzuka Kart Championship: 1st
2001: All Japan Kart Championship, ICA Class: 1st Asia Pacific Kart Championship, ICA Class Esso Formula Toyota Racing School scholarship
2002: Kart Euro Championship Esso Formula Toyota Series (1 race)
2003: Esso Formula Toyota Series: 2nd
2004: Formula Renault Italian Championship: 4th (2 wins)
2005: Formula Renault Italian Championship: 1st (6 wins) Formula Renault Euro Championship: 1st (5 wins)
2006: Formula 3 Euro Series: 8th (Rookie of the Year)
2007: Formula 3 Euro Series: 4th (1 win)