Mercedes have announced that James Allison will join the team from March 1 in the newly-created role of technical director.
Allison, who previously won world championships with Ferrari and Renault, took a break from Formula One after the sudden death of his wife in March 2016.
The 48-year-old said: “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. I am really looking forward to playing my part in helping Mercedes go from strength to strength in the coming years.”
Allison will report to Mercedes team boss Toto Wolff, who added: “I am delighted to welcome James to Mercedes and very much looking forward to working with him.
“James is a sharp engineer; I think we have found the perfect guy and the right fit with our senior leaders.”