Steve Mandanda has extended his Marseille contract until 2024.
The OM captain and goalkeeper had been set to leave the club at the end of the 2020-21 season.
A three-year extension will, a Marseille statement said, allow Mandanda to "add even more to the legend".
The 35-year-old, who will be 39 when his new deal expires, has made a club-record 549 appearances for OM.
Mandanda - initially signed from Le Havre in 2007 - had a short, unsuccessful stint with Crystal Palace in the Premier League in 2016-17 before returning to Marseille.
The France international remained Marseille's first-choice keeper last term before the Ligue 1 season was suspended due to the coronavirus pandemic.
Their new campaign is belatedly set to get under way at Brest on Sunday after positive COVID-19 tests prompted the postponement of the first scheduled match.