Arsenal have confirmed the signing of Switzerland midfielder Granit Xhaka from Borussia Monchengladbach.
Sky sources reported at the weekend that Xhaka was in the process of completing the move for a fee in the region of £30m - Arsenal's third-most expensive transfer.
Xhaka subsequently completed his medical and will join up with his new team-mates after Euro 2016, where he is expected to star for Switzerland.
The 23-year-old has been among the outstanding central-midfield performers in the Bundesliga in recent seasons.
Arsenal boss Arsene Wenger said: "Granit is an exciting young player, already with good Champions League and Bundesliga experience.
"We have been watching him for a long time now and he is a player who will add quality to our squad.
"We wish Granit a good Euro 2016 with Switzerland and look forward to welcoming him to Arsenal ahead of next season."
Xhaka joined Monchengladbach in 2012 from his hometown club FC Basel, where he spent 10 years progressing through the youth and senior ranks and won two Swiss titles.
He made over 100 Bundesliga appearances for Monchengladbach and scored six goals.
After paying tribute to his old club, Xhaka wrote on his official Instagram account: "From now on I'm totally focused on playing at one of the biggest clubs in the world.
"It's a big honour for me to wear the Arsenal jersey, as well as it has been an honour to play for Gladbach in the last four years. I hope we see each other again in the Champions League!"
Xhaka believes his aggressive style of play will be well suited to the Premier League.
He told Arsenal media: "I'm an aggressive player and also a leader. I'm only 23 but I captained a good team in Germany.
"I like the style of football in the Premier League. It's aggressive and I like the way Arsenal play football. It's not like other countries but it's very nice here. Yes, it's a fight. I like that but Arsenal can also play football and that's very good.
"In Germany you can play aggressively but the referee will always blow his whistle, but in England that's not the case. That's better for me."