The Paris Saint-Germain superstar is out of contract at the end of the season and will therefore be available to move for free.
Real Madrid tried to sign him this summer for a nine-figure sum, but they ultimately failed with that attempt at convincing PSG to sell their prized asset.
However, the general consensus since the transfer window closed is that Los Blancos will sign Mbappe for free after the conclusion of the 2021/22 campaign.
That's still a very likely outcome, but Barcelona's entry into the race to acquire the Frenchman's coveted signature could throw a spanner in the works.
Why do we say that? Well, despite their well-known financial issues, the Blaugrana are confident that they will be able to offer Mbappe an eye-watering €90 million signing bonus.
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To put that figure into perspective, Transfermarkt state that only 13 transfers in football history have cost more than that amount of money.
Madness, absolute madness.
The report from AS adds that Barcelona feel the offer of a €90 million signing bonus will put them in pole-position, as it's believed Real Madrid will only cough up €50 million in that regard.
Back in 2017, the Catalan club actually passed up the chance to sign Mbappe from AS Monaco and instead brought in Ousmane Dembele in a mega-money deal.
"[Mbappe's] signing was on the table, but the coaches preferred Dembele because they wanted a player to open the field," former president Josep Maria Bartomeu previously said.
That's proven to be a very poor decision by Barcelona four years on.
Will they finally get him this time? It seems unlikely to be honest. The club is on the decline and it appears Mbappe has his heart set on a move to Real Madrid anyway.
If he leaves PSG that is, which is still not guaranteed to happen - especially now that he's found some on-pitch chemistry with Lionel Messi.