Football Superstar, Cristiano Ronaldo, is facing a class action lawsuit in the US over his promotion of Binance, the largest cryptocurrency exchange in the world.
The plaintiffs claim his endorsement led them to make loss-making investments.
They are seeking damages of “a sum exceeding” $1bn (£790m).
The BBC has contacted both Ronaldo’s management company and Binance for comment.
In November 2022, Binance announced its first “CR7” collection of non-fungible tokens (NFTs) in partnership with Ronaldo, which the footballer said would reward fans “for all the years of support”.
NFTs are virtual assets that can be bought and sold, but which have no real-world form of their own – in other words they only exist digitally. Generally, they are used to mark ownership of something, such as a picture or video online.
In a social media video announcing the partnership, Ronaldo told would-be investors “we are going to change the NFT game and take football to the next level”.
The cheapest NFT from the collection was priced at $77 when it went on sale in November 2022 – but one year later, it was priced at about $1.
The claimants allege that Ronaldo’s promotion of Binance led to a “500% increase in searches” for the crypto exchange, which is registered in the Cayman Islands.
They also say it led people to use the firm to invest in what they call “unregistered securities” – such as Binance’s BNB cryptocurrency.
According to the US Securities and Exchanges Commission (SEC), these assets can be considered securities – and so celebrities endorsing them must follow US law.
SEC chair Gary Gensler previously said celebrities must “disclose to the public from whom and how much you are getting paid to promote investment in securities”.
The claimants allege Ronaldo should have disclosed how much he was being paid, but did not.
Nigel Green, boss of consultancy firm DeVere Group, said the problems at the heart of the case went wider than just one footballer.