The winger, after helping Leicester win promotion back to the Premier League last season, has transformed his loan into a permanent move from Sporting CP.
Fatawu told the club's website: “I feel amazing.
“It’s so good to be back and I’m just back to focus again for next season. I feel so much motivation to be in the Premier League. It’s something new to me. I’m going to go hard for that, with the team.
"I can’t wait to see (my team-mates). I’ve missed them so much. They are like a family now. I didn’t think I’d miss some of them, but when I went away, I was really missing them! I can’t wait to see them.”
Fatawu has penned a five-year contract and also said: “With the fans, it feels so good to be with them,” he explained. “They always give more energy and it gives me the motivation to do more. They are the best.
"It’s amazing for me. I always feel good when I hear the fans singing my name. That will keep me going.”