Bayern needed a new manager after deciding to part company with Ancelotti, who lost the faith of the squad, was criticised for his lacklustre training sessions and suffered a humbling defeat against Paris Saint-Germain in the Champions League.
"There's a great mutual trust between Jupp Heynckes and FC Bayern".
Heynckes first managed Bayern between 1987 and 1991 before returning as caretaker boss in 2009.
Bayern Munich may have gotten in Jupp Heynckes for the remainder of the season but their long-term choice still remains a mystery.
Heynckes said: "I would not have returned to any other club in the world but Bayern Munch is a love affair for me".
Heynckes had previously told German publication Kicker that his appointment was an act of friendship and not a comeback. "I don't want to come back earlier than that but inside I still want to coach every single day, therefore I don't think I would join a national team".
The 72-year-old has been named as manager until the end of the season, in his FOURTH spell back at the Bundesliga giants.
"For now I'll have 10 months off and then I'll start looking for a new club", he said.
Heynckes confirmed he has met with Bayern Chairman Karl-Heinz Rummenigge, president Uli Hoeness and Director of Sport Hasan Salihamidzic. We are very grateful to Jupp.
Meanwhile, Hermann, who was assistant to Heynckes when Bayern won the treble in 2013, confirmed to Bild that he had asked him to be relieved of his position as Fortuna's assistant until the end of the season.
Italian Ancelotti took over last season, but was sacked last week after the German champions slipped to second place in the league after twice squandering a two-goal lead in consecutive games.