Sunderland have confirmed the arrival of Patrick van Aanholt from Chelsea on a four-year contract.
The 23-year-old Dutchman had been tipped to make a loan move to the Stadium of Light, but the Black Cats have gambled to sign him permanently for an undisclosed fee.
Gus Poyet has been in the market for a left-back ever since Marcos Alonso's loan deal from Fiorentina expired at the end of last season, with Phil Bardsley and Andrea Dossena having also moved on.
Van Aanholt is a full Netherlands international, but only made eight senior appearances for the Blues and was loaned out on seven occasions, most recently to Vitesse Arhem for three consecutive years.
He has Premier League experience from a spell at Wigan Athletic, where he made only three starts. He played in the Europa League for Vitesse last campaign and was named in Holland's provisional World Cup squad.