The Serie A powerhouse have named previous Italy head coach the veteran manager to take the helm for the remainder of the campaign.
Spalletti replaces the Croatian manager, who was dismissed after the Serie A side's defeat by Lazio on Sunday.
Tudor arrived at the club in March to replace Thiago Motta but departed after seven months following a string of eight matches without a victory.
Spalletti led Napoli to the Serie A title in 2022-23 before taking charge of Italy, which missed out on the 2022 World Cup during Roberto Mancini's tenure.
He secured their spot in 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, 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 secured two Russian Premier League titles with Zenit St Petersburg.
Massimo Brambilla served as interim manager for Juventus in the midweek 3-1 triumph over Udinese moving them to seventh position in the league - trailing leaders Napoli by six points after nine matches.
Their Champions League campaign sees them in 25th place in the group stage, after recording one defeat and two ties in the initial three fixtures.
