Watford have signed Birmingham City left-back Mat Sadler for £750,000 on a three-and-a-half year deal.
Sadler could be set for an immediate debut as he is eligible to play in the FA Cup against Wolves on Saturday.
The Hornets are defensively short following the premature end of Calum Davenport's loan move and with Danny Shittu at the Africa Cup of Nations.
Sadler has been out of favour at St Andrew's since losing his place during Birmingham's promotion run-in in April.
And, having been kept out by both Stephen Kelly and Franck Quedrue, he was further knocked down the pecking order at St Andrew's by the arrival of Hibs left-back David Murphy.
Sadler could eventually cost Adrian Boothroyd's side up to £900,000 depending on appearances and Blues have also installed a sell-on clause.