Newcastle have signed Federico Fernandez on a four-year deal for an undisclosed fee from Championship Swansea.
Newcastle confirmed the signing of the 29 year old on their official Twitter page.
Fernández signed for Swansea in the summer of 2014 and made more than 100 Premier League appearances for the Welsh club.
Speaking about his arrival on Tyneside, Fernández said: "It was a long day but I'm really happy to be here.
"It's a new challenge in my life and I'm very excited to meet all the players and staff here."
Boss Rafa Benítez added: "I know Federico well from our time together at Napoli and it was an easy decision to bring him here.
"He is experienced, a very good professional and he will add competition in defence."