Leonardo Bonucci sensationally returned to Juventus from AC Milan on Thursday, with Gonzalo Higuain and Mattia Caldara moving the other way to the San Siro.
Bonucci won six Serie A titles in seven years at Juventus but the Italy defender joined Milan last year — in what was the shock of the transfer window — for a fee of more than 40 million euros ($45 million) amid reports of a dressing room spat.
The 31-year-old Bonucci, who has reportedly taken a pay cut to move back to the club, signed a five-year deal. He was jeered by some Juventus fans on his arrival at the club's headquarters on Thursday.
"It's an emotional day," Bonucci said. "Turin is my home and Juventus is my home and I'm happy to be back."
Bonucci was given the captain's armband at Milan but struggled initially and only returned to somewhere near his best in the second part of the season.
He celebrated wildly after scoring at Juventus in his first match against his former team, having been booed non-stop by the home supporters.
Milan finished sixth in Serie A last season, 31 points behind champion Juventus.
Juventus said in a statement that Bonucci and Caldara are direct swaps with each player being valued at 35 million euros ($41 million).
Caldara signed a five-year deal at Milan.
The 24-year-old Caldara is set to form a partnership with Alessio Romagnoli, with the duo widely viewed as two of Italian football's finest young defenders.
Caldara burst onto the scene two seasons ago with seven goals for Atalanta. That persuaded Juventus to sign him in January 2017, but the Bianconeri loaned him back to Atalanta until this June.
The 23-year-old Romagnoli is expected to take over the captain's armband from Bonucci.
Higuain is the only player who has moved initially on loan, with Milan paying 18 million euros ($21 million) for the services of the 30-year-old Argentina forward for next season. The Rossoneri have the right to buy Higuain for 36 million euros ($42 million) at the end of the campaign.
Juventus spent an Italian record 90 million euros (then $99 million) to sign Higuain from Napoli in 2016 after he scored 36 goals in his last season to break a 66-year-old Serie A record. He scored 32 goals in his first season at Juventus.
The lack of a regular goalscorer is arguably Milan's biggest weakness at the moment.
Juventus broke that record transfer fee last month by signing Cristiano Ronaldo from Real Madrid for 112 million euros ($131.5 million).
"I think it was the right deal both for us and for Milan," said Juventus coach Massimiliano Allegri earlier on Thursday. "Bonucci is coming back to us after a year. He's an important footballer, gifted with great skill and personality, and he hasn't changed at all in six months.
"With regards to Mattia, I'm sad, together with Romagnoli and (Daniele) Rugani, he's part of a trio of young defenders who are the strongest there are in Italy, but that's the transfer market and we had to let him go ... I thank Higuain. He has given everything in the two years he has been with us. Milan has certainly got a great forward."
FLORENZI COMMITS TO ROMA
Roma midfielder Alessandro Florenzi extended his contract with the Serie A club until 2023.
Sporting director Monchi said: "For us Alessandro isn't just an important footballer, but he's one of our emblems."
The 27-year-old Florenzi progressed through the ranks at Roma and made his debut in 2011 as a substitute for Francesco Totti.
Florenzi, who spent a year on loan at Crotone, has scored 25 goals in 222 matches for Roma. He scored an astonishing equalizer from near the halfway line against Barcelona in the group stage of the 2015-16 Champions League.
The Italy international is a versatile footballer, who can also play as full back or winger.
He has scored two goals in 28 matches for Italy.
(With AP Inputs)