Casemiro is delighted with his return to Real Madrid.
The midfielder spent last season with Porto.
Casemiro said: "It was an extremely important year in my life. Porto helped me quite a bit but I worked really hard, with lots of enthusiasm and humility and with my mind always focused on returning to Real Madrid. It was a fantastic year on a personal level.
"I'm living another dream and it feels like I've returned home. I was gone for a year but I was always thinking about being at Real Madrid. I'm really excited about triumphing here."