Mercedes engine boss Andy Cowell is to leave his post next month, the Formula One team have announced.
Cowell has been instrumental in the cars that have dominated F1 over the past half a dozen seasons.
Mercedes have won the constructors' championship in each of the past six years and Lewis Hamilton has won five of the drivers' titles, with former team-mate Nico Rosberg emerging victorious on the only other occasion in 2016.
Cowell, 51, has spent the past 16 years in a senior role at Mercedes and his position as managing director for the F1 power unit will be filled by Hywel Thomas from July 1.
"Andy's leadership of the team at HPP [High Performance Powertrains] has been a key factor in our championship success in recent seasons," Mercedes team principal Toto Wolff said.
"He has made an outstanding contribution to our motorsport legacy and I have valued and enjoyed our working relationship since 2013; I am sure he will enjoy great success in the next challenge he decides to take on."
The 2020 F1 season is yet to begin because of the coronavirus pandemic, though the Austrian Grand Prix on July 5 has been identified as the likely start date.