Williams have confirmed the long-anticipated appointment of Paddy Lowe as chief technical officer.
Lowe oversaw three years of spectacular dominance at Mercedes after being appointed executive director (technical) at the Silver Arrows in 2013.
James Allison has since taken over his old role with the constructors' champions, allowing Lowe to re-join the team his Formula One career began with in 1987.
Mercedes-powered Williams slipped to fifth in the standings last season after consecutive third-place finishes and will hope that Lowe - who has contributed to five constructors' titles and over 150 race wins in his career - can lead a revival.
Lowe said of his appointment: "I've always had a deep respect for Williams - my first team in Formula One.
"It is a huge honour to return in this leadership position and to have the opportunity to become a shareholder. I am extremely motivated to play my part in bringing success back to the team."