Arsenal have confirmed the arrival of Portuguese left-back Nuno Tavares from Benfica.
The 21-year-old has become the Gunners' first arrival of the January transfer window and is believed to have penned a five-year deal with Mikel Arteta's side.
Benfica will reportedly pocket around £6.8m from the sale of Tavares, who leaves the Portuguese club having scored one goal and assisted seven more in 41 appearances, and he will provide backup and competition to Kieran Tierney at the Emirates.
Speaking to the official Arsenal website, technical director Edu said: "Nuno is a talented young player who was wanted by a number of clubs across Europe. He will provide strong back-up in the left-back position. We look forward to him growing and developing with us and becoming an important member of the first-team squad."
Arsenal manager Arteta added: "We welcome Nuno to the club. He is a young player with great promise who has developed very well with Benfica in recent seasons and has also shown his quality by being part of Portugal Under-21s.
"Nuno's arrival will give the squad extra strength and options in defence, particularly with this energy on the left side of the pitch. We look forward to Nuno's arrival soon, his integration into the Arsenal family and playing in front of our fantastic supporters."
Tavares made a cameo appearance against Arsenal for Benfica during last season's Europa League and will wear the number 20 shirt for the Gunners.