Midfielder Mikel Merino has completed his move to Arsenal from Real Sociedad in a deal understood to be worth 37.5 million ($41.9m), the north London club announced on Tuesday.

The 28-year-old, who has signed on a four-year deal, was part of the Spain team that lifted the Euro 2024 title, contributing most notably with an extra-time winner against Germany in the quarterfinals.

The deal is thought to be 32.5m plus 5m in add-ons.

Arsenal sporting director and former midfielder Edu said of the transfer: "We are so happy to have completed the transfer of Mikel Merino. This has been another great team effort from many people at the club to finalise the transfer of a player who attracted interest from a number of clubs over the summer.

"Mikel was a key target for us this summer, and we identified him as a player who can fit perfectly into our squad and profile to improve us, as we aim to build on our strong performances of last season."

Real Sociedad coach Imanol Alguacil left Merino out of the squad for their LaLiga opener against Rayo Vallecano due to talks advancing with Arsenal at the time of the match, and he also did not feature in the team's win over Espanyol last weekend.

Merino played 242 times for Real Sociedad, scoring 27 goals and adding 30 assists after signing for the Basque club in 2018.

Arsenal coach Mikel Arteta has been a fan of the player for some time, and believes his profile -- and evolution in recent seasons -- is what his team needs to pursue the Premier League title.

"Mikel will make our squad significantly stronger, with his technical ability, together with his strong and positive character and personality," Arteta said in the news release announcing Merino's arrival.

Information from ESPN's James Olley contributed to this report.