Juventus have named ex- Italy manager the veteran manager to lead the team for the remainder of the campaign.
Spalletti replaces the Croatian manager, who was let go following the loss to Lazio last weekend.
Tudor arrived at the club in March filling the shoes of Thiago Motta but exited following a seven-month stint at the end of an eight-match winless run.
Spalletti led Napoli to the Serie A title in 2022-23 prior to assuming the Italy role, after the team's failure to reach the 2022 World Cup under former boss Roberto Mancini.
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 following a loss to Norway in World Cup qualifying, with the Azzurri at risk of missing out on a third consecutive World Cup.
Spalletti has also managed Inter Milan, Roma and Udinese in Serie A and won the Russian Premier League twice with Zenit St Petersburg.
Juventus were temporarily led by Massimo Brambilla for their 3-1 win against Udinese on Wednesday placing them seventh in the Serie A standings - six points behind leaders Napoli after nine games.
In the Champions League, they sit 25th in the league phase, after recording one defeat and two ties in the initial three fixtures.
