Mercedes have confirmed the appointment of James Allison as their new technical director.
Allison, who has held the same role at Renault and Ferrari, arrives as a replacement for Paddy Lowe, who is expected to join Williams, although no official announcement has yet been made to that effect.
The 48-year-old left Ferrari in July last year and will begin his tenure with the Silver Arrows on March 1, with the 2017 Formula One season starting in Melbourne later that month.
He has won world titles at Ferrari and Renault and will be expected to lead Mercedes to a fourth successive constructors' championship, while Lewis Hamilton and Valtteri Bottas will battle to extend the run of three straight drivers' titles.
"I am very excited to be getting back to work after this time away from the sport. 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," said Allison.
"I am really looking forward to playing my part in helping Mercedes go from strength to strength in the coming years."
Mercedes' head of motorsport Toto Wolff added: "I am delighted to welcome James to Mercedes and very much looking forward to working with him.
"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."