Lionel Messi has signed an agreement worth more than $20 million to promote digital fan token company Socios.com, a source close to the deal told Reuters on Tuesday.

Messi becomes the latest global sports personality to enter the crypto world, following Tampa Bay Buccaneers quarterback Tom Brady and Los Angeles Lakers star LeBron James. Messi's deal also comes amid a growing wave of tie-ups between crypto firms and football.

- Stream ESPN FC Daily on ESPN+ (U.S. only)
- Don't have ESPN? Get instant access

Messi, whose move from Barcelona to Paris Saint-Germain in August included a cryptocurrency payment, will be involved in a publicity and promotion campaign for Socios in the build-up to the Qatar World Cup, which starts in November.

The "ambassador" deal for Messi does not include crypto payments and is a three-year agreement, the source said.

Socios have signed deals, including creating tokens, for more than 130 sports organisations including a number of top football clubs such as PSG, Barca, Juventus and Manchester City.

Fan tokens are a type of cryptocurrency that allow holders to vote on mostly minor decisions related to their clubs.

"Fans deserve to be recognised for their support. They deserve opportunities to influence the teams they love," Messi said in the statement.

"Socios.com exists to enhance the fan experience, to enable fans to 'be more'. I'm proud to join Socios.com's mission to create a more connected and rewarding future for fans around the world."

The tokens are increasingly seen by clubs as a source of new revenue but have been criticised by some supporters groups who see their introduction as superficial participation that adds to the already growing costs of following their teams.

Brady last year took an undisclosed equity stake in crypto exchange platform FTX Trading Ltd and became an ambassador for the company.

In January, James announced a multiyear partnership with Crypto.com, a company who recently signed a sponsorship deal with world football's governing body FIFA.