The Serie A powerhouse have chosen former Azzurri manager Spalletti as their manager for the rest of the term.
The experienced coach takes over from his predecessor, who was let go after the Serie A side's defeat by Lazio last weekend.
Tudor arrived at the club in March filling the shoes of Thiago Motta but departed after seven months following a string of eight matches without a victory.
Under Spalletti, Napoli clinched the Serie A championship in 2022-23 before taking charge of Italy, which missed out on the 2022 World Cup during Roberto Mancini's tenure.
He helped them qualify for Euro 2024 exiting in the last 16 stage against 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 lifted the Russian league trophy twice while at Zenit St Petersburg.
Massimo Brambilla served as interim manager for Juventus in the midweek 3-1 triumph over Udinese placing them seventh in the Serie A standings - trailing leaders Napoli by six points after nine matches.
They are 25th in the league phase of the Champions League, after recording one defeat and two ties in the initial three fixtures.
