Patrick van Aanholt has signed a new contract with Sunderland that will keep him at the club until June 2020.
The Netherlands international's previous deal was due to expire at the end of the 2017-18 campaign, but he has now agreed to a two-year extension.
Van Aanholt joined Sunderland from Chelsea in 2014 and has since developed into a key figure at the Stadium of Light, scoring five goals in 69 appearances in all competitions.
The 25-year-old played a key role in Sunderland's Premier League survival in 2015-16 and manager Sam Allardyce has voiced his delight with the left-back's decision to stay put.
"Patrick was an outstanding performer last season, contributing not only solid defensive performances, but also assists and vital goals," Allardyce commented on the club's official website.
"It is fantastic to be able to secure the long-term services of such a talented footballer and athlete, who will hopefully continue to improve here for many years to come."
Van Aanholt came through the ranks of the PSV youth academy, but left the Eredivisie champions for Chelsea before breaking into the first team.
He only made a handful of starts, though, and spent much of his time on loan before eventually leaving Stamford Bridge for Sunderland.