Chelsea have completed the signing of Spain left-back Asier del Horno for £8m from Athletic Bilbao.
Del Horno scored Spain's winner against England last year
The 24-year-old defender has agreed a three-year deal and will officially become a Blues player on 1 July.
Chelsea boss Jose Mourinho said Del Horno would be a big asset in the club's pursuit of major honours.
"Asier is an outstanding international player who will add quality to the squad in a position we needed to strengthen," said Mourinho.
Chelsea have been keen to boost their options on the left side of defence.
When England international Wayne Bridge suffered a double fracture of his left ankle in February, William Gallas was forced to play out of position.
Chelsea chief executive Peter Kenyon told the club's website: "Jose identified his target to fill the left-back position and we're delighted Asier has chosen to come to Chelsea.
"The arrival of Asier signifies Chelsea's desire to strengthen the squad in key positions following a hugely successful season and we all look forward to seeing Asier in the blue of Chelsea in July."
Del Horno, who came through the ranks at Bilbao, made his debut for Spain last September in a friendly against Scotland and scored the winner against England in November.