Kimi Raikkonen has signed a new contract to remain with Ferrari next season which will keep him at the team for at least another season.
Raikkonen's current deal was due to expire at the end of the year but the Finn, who turns 38 in October, will be handed at 12 more months year with the Italian team.
Sebastian Vettel, who leads Lewis Hamilton in the championship by 14 points, is out of contract with Ferrari at the end of the year, but is yet to confirm his whereabouts for 2018.
"Scuderia Ferrari has renewed its technical and racing agreement with Kimi Raikkonen," the Italian constructor said in a short statement ahead of this week's Belgian Grand Prix.
"The Finnish driver will therefore race for the Maranello team in the 2018 Formula One World Championship."
Raikkonen is 86 points behind team-mate Vettel as Formula One prepares to return to action following its traditional mid-season break.
Raikkonen, the 2007 world champion who will now extend his grand prix career into a 16th campaign, is yet to win a race since his return to Ferrari in 2014.
But the former McLaren and Lotus driver has proved an able deputy to Vettel this season.
Vettel, who won the last round in Hungary to extend his lead over Hamilton in the title race, is yet to confirm whether he will stay at Ferrari next season. The four-time champion has been of interest to Mercedes, with Valtteri Bottas also out of contract at the end of the year.
However, it is expected that Mercedes will hand Bottas a new deal, and with Hamilton also under contract for at least one more year, it seems unlikely Vettel will leave the Italian team at the end of the current campaign.
With Daniel Ricciardo and Max Verstappen also to remain at Red Bull, it could mean the top three teams head into next season with unchanged line-ups.
Double world champion Fernando Alonso is the other major driver yet to formalise where he will be driving next year.
McLaren have been unable to offer the two-time champion a competitive car, but the British team, despite their troubles with engine manufacturer Honda, could be his only option to stay on the grid in 2018.