Former McLaren technical director Paddy Lowe is joining Mercedes after an agreement was struck between the rivals.
Lowe will assume the role of executive director from June 3, with a focus on technical matters, and work alongside team principal Ross Brawn.
Mercedes emphasized that Brawn "will retain overall responsibility for technical and sporting matters," countering reports that his position was under threat.
And Brawn welcomed Lowe's arrival in the statement on Monday, saying he would "strengthen our organisation."
"I am delighted to welcome Paddy to the team and to begin working together," Brawn said. "He has an excellent record of success in the sport and would be an asset to any of our rivals in the pit lane."
Lowe has been on leave since it was confirmed ahead of the 2013 season that he was leaving McLaren.
Lowe will be reunited with former McLaren driver Lewis Hamilton at Mercedes.
"I am excited to become part of a highly talented and capable technical organisation," Lowe said. "The team has already produced probably the fastest car of the 2013 season while the technical challenges of the new regulations for 2014 will give us the opportunity to maximize the synergies available to a works manufacturer.
"That is a challenge I am relishing."