"This is a very important challenge in my career and is a real motivation," he told the club's official website.
"This is something that I have dreamt about from a young age and I have always wanted to play in the Champions League. Signing for Valencia CF has made my dream a reality.
"I always watched La Liga and the Champions League on the television as a child, dreaming of getting to play in those competitions one day. Valencia CF offer me the opportunity to do this and I will give my all to ensure that I don't let them down.
"Now I will have tougher demands on me, a lot of competition and great players around me who are going to push me even harder than before. Obviously this will improve me as a player, which will in turn transfer over to my national team form."