Courtois said at his official unveiling: "Arriving at the best club in the world is a responsibility and an honour".
Champions League-winning goalkeeper Keylor Navas is hell-bent on staying at Real Madrid despite the arrival of Thibaut Courtois.
However there is no clause in the deal that would permit Chelsea to automatically buy Kovacic, a Croatia global, next summer.
Courtois has passed a medical in the Spanish capital and put pen to paper on a six-year contract.
Explaining the reasons for his move, the Golden Glove victor at World Cup 2018 said: "I wanted to be closer to my family".
Indian playing XI for the second Test leaked
Chris Woakes will come in if England opt for a further seam option, while Moeen Ali will play if the hosts plump for two spinners. Yet this season has seen Pope make 684 runs for Championship leaders Surrey at an average of 85.5, including three centuries.
As displayed by Manchester City's Ederson, whose previous world record fee now looks like a bargain, a keeper that can be composed under pressure and deliver smart passes is a huge advantage to have in the Premier League.
Kepa had been with Athletic since 2004, rising through the youth ranks.
"It's been a very important decision for me", he said.
Arrizabalaga becomes the most expensive goalkeeper in soccer history, ahead of Liverpool's Alisson, who moved from AS Roma for €75 million earlier in the transfer window.
"The Croatian midfielder joined Marcelo, Varane, Casemiro and Kovacic, who did individual work in the gym".