Real Madrid have expressed "gratitude and appreciation" to "exemplary player" Casemiro ahead of his move to Manchester United.
United have agreed a fee reported to be £60million plus £10m in add-ons to take the midfielder to Old Trafford.
The Brazil international is set to sign a four-year deal with the Red Devils, who are bottom of the Premier League after losing their first two Premier League games under new boss Erik ten Hag.
Casemiro joined Los Blancos in January 2013 at the age of 20 and has gone on to win 18 trophies - including the Champions League five times, three LaLiga titles and the Club World Cup on three occasions.
The 30-year-old will appear before the media in the press room at Real Madrid City on Monday, when president Florentino Perez will be present as the LaLiga champions stage a ceremony to bid farewell to the long-serving enforcer.
Madrid paid tribute to Casemiro after confirming a deal has been agreed with the Red Devils on Friday.
A statement on the club's official website said: "Real Madrid would like to express its gratitude and appreciation to Casemiro, who is part of the club's history."
After listing his many honours during his time in the Spanish capital, the European champions added: "In addition to this brilliant list of achievements, Casemiro will always be remembered by the Madridistas as representing the values of our club. An exemplary player who has given his all for Real Madrid.
"Real Madrid is and always will be his home, and we wish him and all his family the best of luck in this new chapter of his life.
With United facing Liverpool on the same day of Casemiro's press conference in Madrid, his debut could come at Southampton a week on Saturday.