In a statement Fiorentina said that Juventus had paid to take the 22-year-old to Turin, although they did not reveal the fee paid, and that the Italian champions would buy Chiesa at the end of the loan period.
The transfer was revealed by Serie A on Monday, before either club made an announcement, when it included the move among the list of completed deals on its website.
The move is reported to be worth between 55 million and 60 million euros ($65 million and $71 million), with 10 million euros for the loan, 40 million for the eventual sale and between 5-10 million in add-ons.
Chiesa, who is reported to have agreed a five million euro annual salary with Juve, had been pictured having his medical in Florence before joining the Italy squad ahead of the the three matches facing Roberto Mancini's 'Azzurri' over the next 10 days.
His arrival at Juve follows the departures of defenders Daniele Rugani and Mattia De Sciglio to Ligue 1 teams Rennes and Lyon respectively and Bayern Munich-bound Douglas Costa.
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