He signs a contract that will keep him at the club until 2022, although there is a release clause of €100million should any club ever feel the need.
Despite his Algerian heritage on his father's side, Berchiche was born in Zarautz in the Basque country to a Spanish mother, coming through the youth academy at Real Sociedad and qualifying him to play for Bilbao.
He was then picked up by Tottenham and spent two years in England, beofre returning to Spain with Real Unión.
He then went back to Sociedad before an impressive two seasons on loan at Eibar sparked the interest of PSG.
He has played 22 times in Ligue 1 last season, scoring once, but it was only to be a one-year stay in France.
Internationally, despite being approached by Algeria, he has always declined - holding out hope that a Spain cap may be forthcoming.