Celtic have announced that captain Scott Brown has agreed a new two-year contract extension to keep him in place until 2019.
Central defender Jozo Simunovic, who made the switch to Glasgow from Dinamo Zagreb in 2015, has also been tied down by a further four years.
Brown was due to be out of contract at Parkhead at the end of the current season, but after once again playing a key part for the Hoops last time out he has been rewarded with fresh terms.
The 32-year-old has won seven top-flight crowns, three Scottish Cups and three Scottish League Cups during his decade-long stint at the club.
Simunovic has started eight games for Celtic so far in 2017-18, meanwhile, as they attempt to repeat last season's unbeaten domestic campaign.