Manchester City have announced the signing of defender Nicolas Otamendi from Valencia on a five-year contract.
The centre-back becomes City's third big signing of the summer, following Raheem Sterling and Fabian Delph. Sky sources understand the fee was £33m.
Otamendi, who helped Argentina reach the Copa America final this summer along with his new City team-mates Sergio Aguero, Martin Demichelis and Pablo Zabaleta, will wear the No 30 shirt.
Otamendi told the club's website: "I am very happy because I am coming to an amazing club. The chance to play in the Premier League and enjoy every game, signing for a club that looks wonderful from the outside, having now the opportunity to enjoy it from inside... it's a huge joy for me.
"It would be a dream to fight for the Champions League and win the Premier League. A club like City has to aspire to these kind of things.
"I am here to give my best, to fight game by game and push City to the highest peaks for as long as possible and I wish we will be able to win several cups and titles."
Manager Manuel Pellegrini added: "Nicolas Otamendi was arguably the best defender in La Liga last season and so naturally I'm delighted to have added a player of his quality.
"He is an established international for one of the best nations in world football and I have no doubt that he has the right mentality to fit into a squad where he will find many familiar faces, including Eliaquim and Fernando who he played alongside in Portugal.
"As a footballer, Nicolas has all of the qualities to be a success in the Premier League - he's strong, he's excellent in the tackle and he's very good technically.
"I am sure he will become another Argentine player our fans will enjoy watching."