Juventus have signed Italy international defender Angelo Ogbonna from city rivals Torino.
The 25-year-old has signed a five-year deal, with Antonio Conte's side paying €13million, to be staggered in installments over the next three years.
Juve could also pay their neighbours a further €2m if stipulated "sporting targets" are met during his time with the club.
Ogbonna made his Torino debut in 2007 against Reggina and has gone on to make 159 appearances, scoring only once, against Cesena in April 2010.
He has played six times for the Italy national team and was called into Cesare Prandelli's UEFA Euro 2012 squad, despite having played the previous season in Serie B.
Ogbonna is Juventus' third signing of the season as they look for a third consecutive Serie A title, following strikers Fernando Llorente and Carlos Tevez.