Bayern Munich have appointed former coach Jupp Heynckes as their manager until the end of the season following Carlo Ancelotti's sacking.
Ancelotti left in September with Bayern third in the Bundesliga, five points behind leaders Borussia Dortmund.
Heynckes, 72, has coached Bayern three times before, most recently in 2013 when the side won the Champions League, Bundesliga and German Cup treble.
"I would not have returned to any other club in the world," he said.
"Bayern Munich is very close to my heart. My coaching staff and I will now do everything to bring back successful football for the fans. I'm very much looking forward to this challenge."
Bayern are in Celtic's Champions League group and the teams face each other twice before the end of October.
Heynckes considered retiring in 2013 after he was replaced by Pep Guardiola and at the time said he would not coach again in the Bundesliga.
But he will take over again at the club on Monday and his first game in charge of Bayern for a fourth time will see the German champions host SC Freiburg on Saturday 14 October.