Hoffenheim manager Julian Nagelsmann will leave at the end of next season to become head coach of Bundesliga rivals RB Leipzig.
The 30-year-old took over at Hoffenheim in February 2016 and led them into the Champions League for the first time.
He was under contract until June 2021 but activated an exit clause to sign a deal with Leipzig until 2023.
Ralph Hasenhuttl left Leipzig in May after they finished sixth. They are set to appoint an interim coach.
Hoffenheim said they plan to announce Nagelsmann's successor "in the winter".
Nagelsmann, who became the youngest manager in Bundesliga history when he was appointed by Hoffenheim at the age of 28, has been linked with a move to the Premier League.
He helped Hoffenheim avoid relegation in 2015-16, led them to a fourth-place finish in 2016-17 and third place last season to reach the Champions League group stage for the first time.
"It was important to me to ensure clear conditions early," Nagelsmann said.
"Now everyone knows what they are about and we can focus professionally on the upcoming, heavy tasks.
"Everyone knows that I will be burning and doing everything I can to reach our ambitious goals until the last hour of my commitment to TSG."