Argentine soccer star Lionel Messi’s transfer to French club Paris St Germain included a payment in cryptocurrency fan tokens, a source close to the matter said, providing another big name endorsement for new digital assets.

Messi, 34, left Spanish side Barcelona and signed a two-year contract with Paris St Germain (PSG), with an option for a third year, on Tuesday.

Paris St Germain (PSG) said in a statement the tokens included in his “welcome package”, or signing on fee, had been provided by Socios.com who are the club’s fan token provider.

The club did not state what percentage of the deal comprised the tokens but said he had received a “large number”. It has also not disclosed the overall financial package.

Fan tokens are a type of cryptocurrency that allow holders to vote on mostly minor decisions related to their clubs. Among the clubs to launch tokens this year are English Premier League champions Manchester City and Italy’s AC Milan.

Like bitcoin and other digital currencies, fan tokens can be traded on exchanges. They also share in common with other cryptocurrencies a tendency for wild price swings, leading some financial regulators to issue warnings to investors.

PSG said there had been high volume of trading of its fan tokens after reports of Messi’s move to the club emerged.

“The hype surrounding the latest signings in the club’s busy summer transfer window created a huge surge of interest in $PSG Fan Tokens, with trading volumes exceeding $1.2 billion in the days preceding the move,” it said.

The fan tokens’ price moves can have little connection to on-field performance or results.

PSG’s token, which has a market capitalisation of about $52 million, soared over 130 percent in just five days amid speculation over Messi’s arrival to an all-time high of over $60 on Tuesday. They were last down 10 percent at about $40, according to the CoinMarketCap website.