Former Ferrari technical chief James Allison will return to Formula 1 on March 1 with Mercedes as their new technical director.
Allison took an extended break from the sport following the passing of his wife and rejected an early opportunity to come back last October with Renault.
The 48-year-old, who has played a senior role in delivering World Championships with both Ferrari and Renault, will report directly to Toto Wolff in a newly-created role.
"I am very excited to be getting back to work after this time from the sport," Allison told the official Mercedes website.
"It's a massive privilege to be given the trust of a position in a team that has done so spectacularly well in the past three seasons.
"I am really looking forward to playing my part in helping Mercedes go from strength to strength in the coming years."
Mercedes boss Wolff welcomed the arrival of Allison and believes he make a big impact in his new role.
"I am delighted to welcome James to Mercedes and very much looking forward to working with him," Wolff added.
"Our technical team is extremely skilled at every level and at the top of its game after delivering three world championships in a row.
"It wasn't an easy task to find the right personality who can strengthen our experienced group of engineers, give our talented young team members the space to develop and also bring his own vision to this role.
"James is a sharp engineer. I think we have found the perfect guy and the right fit with our senior leaders."
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