London: Nick Heidfeld was named Mercedes reserve and test driver for the 2010 Formula One season on Thursday.
"Whilst I would of course have preferred a seat as an active driver, I am really proud to be part of the new Silver Arrows team. I have seen how committed everyone at the team is and I feel the same," Heidfeld said in a statement.
The German, who last raced for BMW Sauber between 2006 and 2009 and has competed in 167 grands prix, will be backup for returning seven-times world champion Michael Schumacher and Nico Rosberg.
Schumacher was tempted out of retirement after Mercedes bought last year`s world champions Brawn.
The arrival of Heidfeld, who started his F1 career with Prost in 2000, completed an all German lineup for Mercedes.
"It`s a great pleasure for us to have signed a driver of the calibre and experience of Nick Heidfeld," team principal Ross Brawn said.
"Nick has over 10 years of experience in Formula One working with established teams and he will be a great asset to Mercedes GP. I am confident that his input into the development of our MGP W01 car will be invaluable."