The 24-year-old has been linked with a move away from Selhurst Park throughout the summer transfer window after impressing for club and country.
Guehi has who has made 113 appearances for the Eagles and has developed a reputation as one of England's best defenders.
The centre-back impressed with his consistent performances in England's run to the Euro 2024 final, featuring in six of his country's seven matches in Germany.
Liverpool are among the clubs who have been credited with an interest in Guehi as they look to bolster Arne Slot's defensive options.
Newcastle close in on Guehi deal
However, it has been Newcastle who have been pushing hard to sign Guehi and their persistence could pay off the closing stages of the transfer window.
According to the Daily Mail, Newcastle are close to reaching an agreement after previously failing with four bids for the Palace defender.
The report claims that the two clubs are in advanced talks and are on the verge of reaching an agreement close to Palace's £70m asking price.
There is a belief that Guehi's future will be resolved in the next 48 hours, with the two clubs looking to make swift progress ahead of Friday's transfer deadline.
Guehi still has to make transfer decision
Even if Palace accept Newcastle's latest proposal, Guehi will have to device whether he wants to complete a move to St James' Park before discussing personal terms.
Newcastle head coach Eddie Howe will hope Guehi gives the green light to the transfer, having earmarked the centre-back as his top transfer target.
The Magpies have already strengthened their backline with the addition of Lloyd Kelly following his Bournemouth departure.
However, they are keen to bring in further reinforcements, with Sven Botman and Jamaal Lascelles continuing to work their way back from long-term injuries.
Newcastle are looking to build a squad that can fight for European qualification after they fell short in the 2023-24 season.