The 29-year-old forward has joined the Spanish side for an undisclosed fee, bringing his two-year stay at St. James’ Park to an end.
Joselu signed for the Magpies from Stoke City in August 2017, and went on to score in his home league debut for the club – a 3-0 win over West Ham United later that month.
In total, the former Real Madrid forward – who had spells with Celta Vigo, Hoffenheim, Eintracht Frankfurt, Hannover and Deportivo La Coruña before arriving on Tyneside from the Potters – made 52 appearances for United, scoring seven times in all competitions.
The club wishes Joselu well for the future.