Bell is one of F1's most respected design engineers
Mercedes GP have appointed Bob Bell, the man behind Fernando Alonso's two consecutive Formula 1 titles, as their new technical director.
Bell, who was lead design engineer for Renault when Alonso won back-to-back drivers' F1 crowns in 2005 and 2006, has also worked for McLaren and Jordan.
Mercedes said in a statement that the move will allow team principal Ross Brawn more freedom to operate.
"Bob will be an important asset to our team," said Brawn.
"His appointment is a key step in the strengthening of our excellent technical team, and we are pleased to have recruited one of the most experienced engineers in the sport."
Bell said: "It will be a privilege to be a part of such a strong and determined organisation, and to be able to contribute to furthering the enviable heritage of Mercedes-Benz in motorsport."
Bell is a highly respected and experienced design engineer, whose speciality is in aerodynamics, and he will be expected to make a significant impact at Mercedes.
The German giant took over the title-winning Brawn team at the end of 2009 and persuaded Michael Schumacher to come out of retirement, but they struggled in 2010, failing to win a race and finishing fourth in the constructors' championship.
Their new car has appeared off the pace in pre-season testing so far, although the team have played down any problems and say it will improve in time for the first race thanks to a raft of development parts.
Bell will help Brawn (centre) get the best out of his drivers
Bell took over as acting team principal at Renault following the sacking of team principal Flavio Briatore and engineering director Pat Symonds in the wake of the Singapore race-fixing scandal in September 2009.
Briatore and Symonds were found guilty by governing body the FIA of asking their driver Nelson Piquet Jr to deliberately crash in the 2008 Singapore Grand Prix to try to ease team-mate Alonso's path to victory.
The crash triggered a safety car and the Spaniard went on to win the race. Bell was not implicated in the scandal.
Following the appointment of new team principal Eric Boullier in January 2010, in the wake of the takeover of the Renault team by investment group Genii capital, Bell was appointed managing director - James Allison had already moved into his former position of technical director.
Bell left Renault in October 2010 in what the team described as "a mutual decision based on the direction the company is taking".