Johan Ackermann will leave South Africa's Lions at the end of the Super Rugby season to become coach of English club Gloucester.
Ackermann will replace former Brumbies coach Laurie Fisher, who quit last month.
The 46-year-old, a former Springbok international, has turned around the Johannesburg-based Lions since taking charge in 2013.
He led the team back into Super Rugby and to last season's Super Ruby final.
The Lions said in a statement that Ackermann's departure was a mutual decision.
He will finish the Super Rugby season with the Lions, who are second in the early-season standings with five wins from six games.