Arsenal FC have paid Real Madrid CF a club-record fee reported to be in the region of 50m to secure the services of Mesut Özil on a long-term contract.
Having only recruited striker Yaya Sanogo and re-signed their former midfielder Mathieu Flamini since the end of last season, the Gunners moved for the Germany playmaker on the final day of the transfer window.
Özil who completed the formalities of the switch in Munich, where he is preparing for his country's forthcoming FIFA World Cup qualifiers against Austria and the Faroe Islands leaves Madrid after three years in the Spanish capital.
"We are extremely pleased to have signed Mesut Ozil," said Arsenal manager Arsène Wenger. "He is a great player, with proven quality at club and international level. We have watched and admired him for some time as he has all the attributes I look for in an Arsenal player."
The ex-FC Schalke 04 player added: "I am thrilled to be joining a club of the stature of Arsenal and am looking forward to playing in the Premier League. It will be great for my own personal development as a player and I am particularly looking forward to working with Arsène Wenger. It is clear the club have huge ambition and I look forward to being part of an exciting future."
A Spanish title winner with the Merengues in 2011/12, the 24-year-old former SV Werder Bremen man leaves Madrid with 19 goals in 105 Liga appearances to his name. Özil, capped 47 times, moved to the Santiago Bernabéu in August 2010 from Bremen for around 15m, following a summer in which he helped inspire Germany to a third-place finish at the FIFA World Cup in South Africa.
A year earlier he was a member of the squad that triumphed at the UEFA European Under-21 Championship in Sweden, Özil scoring in Germany's 4-0 final victory against England.
The Gunners also brought in Italian international goalkeeper Emiliano Viviano on deadline day. Viviano, 27, joins on a season-long loan deal from US Città di Palermo, who were last season relegated to Serie B. "Viviano is a player that we have rated for some time and we are very pleased to have signed him on loan," added Wenger. "He's experienced and has proved himself at a high level, and provides us with excellent cover to our existing goalkeepers."
Arsenal will play Borussia Dortmund, Olympique de Marseille and SSC Napoli in UEFA Champions League Group F.