Lewis Hamilton could make a shock move to Ferrari for the 2025 season, BBC Sport understands.
Several sources say claims of links between the seven-time champion and Ferrari should be taken seriously, but a deal is not yet confirmed.
Ferrari want Hamilton to join Charles Leclerc for the 2025 season.
The 39-year-old signed a new two-year deal with Mercedes for 2024 and 2025 last summer but it seems he can leave after one season, should he choose.
The possibility of Hamilton moving to Ferrari in 2025 was reported in the Italian and Spanish media on Thursday.
BBC Sport has since verified the fact that it is a serious possibility. An announcement could come as early as Thursday.
There have been intermittent rumours of Hamilton moving to Ferrari for years. Until now, these have turned out to have little substance.
But a number of sources say this is different and should be taken seriously.
Ferrari and Mercedes have refused to comment.
Hamilton won the most recent of his seven world titles in 2020.
He signed his latest two-year Mercedes deal in August, which would extend his period with the team to 13 years.
Ferrari admitted to holding talks with then-reigning world champion Hamilton in 2019 about joining them in the future.
Red Bull have dominated the sport over the past two seasons since the controversial 2021 Abu Dhabi Grand Prix, when Hamilton lost out to Max Verstappen after former FIA race director Michael Masi ignored the rules in operating a late-race safety car period.
More to follow.