Ancelotti was sacked by Bayern Munich last month following a 3-0 defeat to Paris Saint-Germain in the Champions League and amid claims relations had broken down between the Italian and a number of his experienced squad members.
Defending In Numbers is a new Deezer Originals football podcast, created by Squawka. "I feel just wonderful!" - quoted Heynckes the German edition of "Kicker". I have a very good feeling. "I can start immediately".
He also took over temporarily at the Allianz Arena following the departure of Jürgen Klinsmann in 2009, whilst in his first spell with the club between 1987 and 1991 he also lead the team to two Bundesliga titles. He was then full time manager again between 2011 and 2013.
It is a fourth spell in charge for the 72-year-old, who had retired in 2013 after leading Bayern to the treble.
The announcement was done via the club's Twitter account saying: "Jupp Heynckes will take over as #FCBayern head coach until the end of the season".
"Bayern is pulling Jupp Heynckes out of retirement", wrote Sport Bild.
"The conversations that [club president] Uli Hoeness, [sporting director] Hasan Salihamidzic and I have now had have also shown this again".
"He is at the moment the ideal coach for Bayern".
On their official website, the man himself revealed: "I would not have returned to any other club, but FC Bayern are a matter very close to my heart".
'My coaching staff and I will now do everything possible to bring successful football back, and I am looking forward to this task'.