Uche has joined on a four-year deal, the young Spanish striker has confirmed.
The 18-year-old told publication AS that he has completed the move from Rayo Vallecano on a four-year deal and Uche will go straight into City's development squad.
"I like the Premier League. Leicester fits the profile, they are hard-working," Uche told AS.
"I think I will adapt well. My style of play is more like English than Spanish football. I have a more physical game.
"Until recently, I did not know much. My agent told me there was someone from England but I did not know the team. When I found out, we went over and decided to sign for them."