Joining Real Madrid marks the fulfilment of a childhood dream for Thibaut Courtois, who won LaLiga with bitter rivals Atletico in 2013-14.
Courtois completed his long-mooted switch from Chelsea to the European champions on a six-year deal and was presented at the Santiago Bernabeu on Friday.
The 26-year-old Belgium international penned his six-year contract before an audience that included his two children, both of whom live in the Spanish capital with his former partner.
“Today I fulfil a dream,” Courtois said. “You cannot understand how happy I am. Those who know me know the effort I have put in to get here.
“My hard work and my feelings have always been about being the best. I have the chance to fulfil a new dream.
“I have dreamt about this since I was a child, admiring those who came on to the pitch to represent Real Madrid.
“I have been a rival and I know what it is to face Real Madrid. Today I’m one of you. Hala Madrid.”