The 19-year-old Ivorian winger, whose transfer from RB Leipzig to Real Madrid could rise to as much as €140m in bonuses on top of a €125m fixed fee, used an extensive Instagram post to thank the Bundesliga club that took a chance on him when he was still a virtual unknown.
"I am incredibly grateful. The club and its management believed in me a year ago, when I had only played a few matches as a professional. They placed their trust in me and gave me the opportunity to prove my worth at the highest level," Diomandé wrote.
The forward went on to reflect on everything he achieved during his brief but intense spell in Germany.
"I was able to establish myself in one of the best leagues in Europe, earn a place in the Ivory Coast national team and represent my country on the biggest stage of all, the World Cup.
"None of this would have been possible without RB Leipzig, and for that I will always be grateful," he said, acknowledging that his rapid rise carries a distinctly German stamp. Diomandé scored 12 goals and provided eight assists in the Bundesliga last season before starring for Ivory Coast at the World Cup.
Diomandé made no attempt to hide his excitement at joining Real Madrid.
"Signing for Real Madrid is a childhood dream come true," he confessed, before thanking the German club for facilitating the transfer despite him still having a contract in place until 2030. The Ivorian also had a warm word for the supporters who backed him during his time at the club: "Your passion, your faith in me and your encouragement meant more than words can express."
The forward closed his message by looking ahead to his new chapter, while leaving the door open to a future reunion.
"Today a new chapter begins. Leaving is never easy, but I am excited for what is to come and I will always remember my time in Leipzig with immense pride," he wrote. "This club will always have a special place in my heart. Who knows? Maybe we will meet again one day in the Champions League."
A final wink that summed up the grateful tone of a fitting farewell.
Diomandé joined RB Leipzig from Leganés for €20m in 2025 after breaking through at the Spanish club, and has now signed a seven-year contract with Real Madrid until 2033, making him the club's most expensive signing and the most expensive sale in RB Leipzig's history.
He arrives in Madrid as part of a busy summer rebuild under new coach José Mourinho that has also brought in Marc Cucurella, Bernardo Silva, Ibrahima Konaté and Denzel Dumfries.