Going through the bar on the BBC Sport homepage is that "Quick" Nick Heidfeld has joined to complete the German line-up at Mercedes.
He will be the reserve driver, but the details of the deal are presently unknown.
Personally I think he is better off as 3rd driver for Mercedes than race driver for say Renault... It may be a gamble that really pays off should Great Uncle Michael fail to complete the season. Although this is looking unlikely at the moment, there is always the possibilty that Schumacher will not be able to finish a full season. Also, should Nico leave at the end of the year Nick is in a prime seat. A coy move from Heidfeld I think, and maybe a very good one.