English Premier League champions Chelsea announced their first signing of the season - Spanish left-back Asier Del Horno - whose services they got for $12 million.

"(Coach) José (Mourinho) identified his target to fill the left-back position and we're delighted that Asier has chosen to come to Chelsea," Chelsea chief executive Peter Kenyon said on the club's website Chelsea Football Club - Official Site for News, Tickets, Fixtures, Video, Mobile & the Chelsea Megastore Shop.

Del Horno joins Chelsea from Spanish club Athletic Bilbao on a three-year deal that begins next month. The deal was finalised late Tuesday night.

"Asier is an outstanding international player who will add quality to the squad in a position we needed to strengthen. I'm sure he will be a key player as Chelsea continues with its goal to achieve greater success both in England and in the Champions League," Mourinho said.

Chelsea have constantly been linked with Arsenal left-back Ashley Cole after Mourinho expressed his desire to strengthen the key position.

The left-back position was an area of weakness for the English champions last season after Wayne Bridge broke his ankle forcing another defender William Gallas to play out of position.

The 24-year-old Spanish international has earned seven international caps and has represented Spain at the youth level from the age of 17.

He has been with Athletic Bilbao from the age of 11 when he joined their junior development programme.