Juventus Re-Sign Atletico Madrid Striker Morata On loan (Photos)
The Spain international, 27, has signed until the end of 2020-21 but Italian champions Juventus have options to extend the loan by 12 months or buy him for a pre-agreed fee.
Juve will pay the La Liga side 10m euros (£9.2m) for each season they have Morata on loan.
He only signed a permanent deal with Atletico on 1 July after a loan spell.
Juventus have the option to buy Morata at the end of this season for about £41m, or after a second campaign on loan for about £32m.
He previously played for Juve between 2014 and 2016, helping them to win two Serie A titles.
The Spaniard has since had permanent spells with Real Madrid and Chelsea, before he initially joined Atletico on an 18-month loan deal.
Juventus are seeking a 10th consecutive league title and started their Serie A campaign with a 3-0 win over Sampdoria on Sunday.