Argentinean international defender Nicolas Otamendi will join La Liga side Valencia from Porto in July for a fee of 12 million euros ($16.2 million), both clubs announced on Wednesday.
"After playing at a very prestigious and big club like Porto, it is an honour for me to now come to one of the most historic and attractive clubs in Spain and Europe like Valencia," Otamendi said in a statement on the Valencia website.
"I am very happy to take this next step in my career."
Valencia had a hectic end to the recently closed transfer window as four first team players left in the final 48 hours, whilst Seydou Keita, Philippe Senderos, Vinicius Araujo and Ruben Vezo all arrived.
Despite not being able to count on any on their new signings from the start, Los Che had a confidence-building 3-2 win away to Barcelona on Saturday as they became the first side since April 2012 to win at the Camp Nou in the league.
However, Juan Antonio Pizzi's men remain 15 points off Athletic Bilbao in the fourth and final Champions League spot.