Casemiro has described his nine-year stint at Real Madrid as "the most wonderful story" as he bid farewell to the club ahead of his switch to Manchester United.
The Red Devils confirmed on Friday that a deal had been struck for the 30-year-old, who has been crucial to Madrid's success in recent seasons, winning the Champions League five times.
It has been widely reported that United are paying £60million (€70.6m) for Casemiro.
Having joined Madrid from Sao Paulo in 2013, Casemiro has established himself as one of the best holding midfielders in world football, and formed a formidable trio alongside Toni Kroos and Luka Modric.
He helped Madrid to a Champions League and LaLiga double last season, and was named man of the match in the Super Cup victory over Eintracht Frankfurt earlier in August, albeit that proved his final start for Los Blancos.
In a post on his social media channels, Casemiro wrote: "I have lived the most wonderful story that I ever thought.
"I hope to return one day to what will always be my home. Not in a thousand lifetimes will I be able to give back to Real Madrid all that you have given me. Forever… Hala Madrid!"
Casemiro's midfield partner in crime Modric posted on Instagram: "What a journey! We had a lot of fun and we made history together. Will miss you my friend."
The Brazil international is repeating the path of Raphael Varane, who last year swapped the Santiago Bernabeu for Old Trafford.
"Many battles fought together with my warrior Case! Welcome to Manchester, amigo," Varane posted on Instagram.