Mercedes has confirmed that Nick Heidfeld has been released from his contract as the team's reserve driver in order to take up the position of official test driver for Pirelli.

As Pirelli prepares for its return to F1, Heidfeld will join the Italian company for a series of tests beginning this week to assist with their development work on the tyre compounds to be used by the Formula One teams in 2011.

"We can confirm that the team is pleased to allow Nick Heidfeld the opportunity to join Pirelli and contribute to their development work for the company's imminent return to Formula One," said Ross Brawn. "Nick is an extremely experienced driver and we are confident that his racing knowledge and technical feedback will prove extremely useful to Pirelli and therefore of benefit to the sport as a whole. Nick has been a real asset to Mercedes since joining our team this year and we are pleased to see his career progressing."

"It was clear from the beginning of our cooperation that Mercedes would release Nick from his obligations as soon as a promising opportunity as an active Formula One driver developed," added Norbert Haug. "This is now the case and there could be no more experienced and knowledgeable driver in the cockpit to steer the tyre development for next season. We thank Nick for his contribution to our team over the last nine months and wish him well with his new challenge. It would be great to see Nick in a competitive car in next year's Formula One World Championship and I am sure his leading role in the new tyre development, in addition to his skills, puts Nick in a good position for the remaining seats in 2011."

"First of all I would like to thank Ross Brawn, Norbert Haug and Nick Fry for allowing me the opportunity to become Pirelli's official test driver," said Heidfeld. "The team has always said that they would not stand in my way if such a chance arose and they have kindly allowed me to take up this exciting new role. I would like to thank everyone at Mercedes for the great cooperation that we have had this year. I have greatly enjoyed supporting the team in my position as Reserve Driver and have felt welcome right from the outset. It was impressive to have the opportunity to work with the current World Champions and I wish the team all the best for the remainder of the season and beyond."