The former Barcelona midfielder signed permanently for Celta last week.
"Iago was picking my brains all month, writing to me and calling me," he said in an interview with the club's official media channels.
"I know many of the members of the squad.
"I am very happy to return to Celta Vigo.
"People have shown to me that they're also happy that I'm back.
"It's a great opportunity to keep growing as a player.
"I was looking for a place where I could feel valued and loved and there's nowhere better than my home.
"Although I could have gone to other places, my number one objective was to return to Celta Vigo.
"I have felt this club since I was little, when I used to come to see matches as a kid."