Crystal Palace have completed the signing of Netherlands full-back Patrick van Aanholt from Sunderland, the London club have confirmed.
The 26-year-old, who joined Sunderland from Chelsea in 2014, has signed a four-and-a-half-year deal to return to England's capital.
Palace did not disclose the fee but it is reported they have paid £14million to sign the left-back, who has played in all but one of Sunderland's matches this season.
He is the second signing made by manager Sam Allardyce, following the arrival of Jeffrey Schlupp from Leicester City for a reported £12m.
Sunderland confirmed the sale with a short statement via their official website, saying: "Sunderland AFC defender Patrick van Aanholt has completed a permanent transfer to Premier League side Crystal Palace for an undisclosed fee.
"The 26-year-old joined Sunderland from Chelsea in the summer of 2014."
Allardyce, who worked with Van Aanholt at Sunderland last season, told Palace's website: "I am delighted that Patrick has joined us. We had great success together at Sunderland where he was instrumental in keeping them in the Premier League last season.
"He will add pace and energy to our team, has strong defensive qualities and has the added ability to score and create goals."
Everton full-back Bryan Oviedo is expected to replace Van Aanholt at the Stadium of Light, with manager David Moyes said to be interested in a double deal for the Costa Rica international and midfielder Darron Gibson.