Juventus have appointed former Italy boss the veteran manager as their manager for the rest of the term.
Spalletti steps in for the Croatian manager, who was let go following the loss to Lazio recently.
Tudor arrived at the club in March filling the shoes of Thiago Motta but left after seven months after an eight-game winless streak.
Spalletti led Napoli to the Serie A title in 2022-23 prior to assuming the Italy role, who had failed to qualify for the 2022 World Cup with Mancini at the helm.
Under his guidance, they made it to Euro 2024 where they were knocked out in the last 16 by Switzerland.
Yet, the Italian FA let Spalletti go in June post a qualifying defeat against Norway, as Italy faced the possibility of not making a third World Cup in a row.
Spalletti has also managed Inter Milan, Roma and Udinese in Serie A and secured two Russian Premier League titles with Zenit St Petersburg.
Massimo Brambilla served as interim manager for Juventus for their 3-1 win against Udinese on Wednesday moving them to seventh position in the league - six points adrift of Napoli at the top after nine rounds.
In the Champions League, they sit 25th in the league phase, after recording one defeat and two ties in the initial three fixtures.
