Arsenal announced on Tuesday the signing of Spanish midfielder Mikel Merino from Real Sociedad for $35 million, with an additional $5 million in potential add-ons.

Merino, 28, had previously informed Real Sociedad of his intention not to renew his contract, which was set to expire on June 30, 2025, if a Premier League offer came through, as revealed on Monday by Real Sociedad president Jokin Aperribay.

The Navarrese midfielder joined Real Sociedad in July 2018 after the club paid $13 million to Borussia Dortmund. Since then, Merino has made 242 appearances, scoring 27 goals and providing 30 assists. He was part of the Spanish national team that won the European Championship in Germany this summer.

Merino, who took part in his first training session at Arsenal's Colney training ground on Tuesday, will wear the number 23 shirt for the Gunners.

"Mikel is a player who will bring great quality with his experience and versatility. He has been with some of the best clubs in the world, and internationally, for several seasons. He will make our squad stronger with his technique, positive character, and personality," said Arsenal manager Mikel Arteta.

"As we saw in the summer, Mikel is also a winner, with his performances helping Spain win the European Championship."

Merino is Arsenal's third signing of the summer transfer window, following the arrivals of David Raya and Tommy Setford.