Bilbao have confirmed Kepa's £72m release clause has been paid ahead of his move to Chelsea.
They released a statement on their official website: “The Professional Football League has certified to our entity that the player Kepa Arrizabalaga has met the requirements for the valid unilateral termination of the work contract that linked him to Athletic Club.
“The aforementioned certification indicates that the player has expressed his desire to terminate and unilaterally resolve the relationship that joined him since the 2004/05 season and that the amount of the compensation established in the contract has been deposited.
“Athletic thanks the player for his contribution during the time he has remained in our Club.
“In this sense, Athletic Club will continue to work so that being part of its first team continues to be the maximum personal and professional aspiration of each and every one of the players, representatives of a unique sporting philosophy and project.
“Our future is built on a choice freely adopted in the past and that only carries a sense of pride.
"Hundreds of players and players who have considered our first team as their aspiration have served this election; and this bet is found both in those who have remained in Athletic throughout their sporting career due to their own desire, as well as in those who have had an unwanted exit resulting from the technical decisions of each moment.
“Players and players protagonists, in short, a genuine personal and collective commitment with which each of the people that make up Athletic can not but feel connected."