Lionel Messi’s most recent contract with Barcelona is worth up to $673 million over four seasons, the El Mundo newspaper reported on Sunday.

The Spanish daily said it had access to the document Messi signed with the Catalan club in 2017, which included fixed incomes and variables that could reach nearly $167 million each season. The newspaper said it is the most expensive contract ever paid to an athlete.

Messi would have to pay about half of that amount in taxes in Spain.

The report said the 33-year-old player has already secured more than $619 million of the total contract. The leak comes as Barcelona tries to manage a huge debt prompted mostly because of the coronavirus pandemic.

The club has been led by a caretaker board since president Josep Bartomeu resigned in October while facing a no-confidence motion. New presidential elections are scheduled for March 7.

The newspaper also detailed how Messi rewarded the club over the years, having helped it win more than 30 titles. Messi has been with Barcelona for nearly two decades but asked to leave at the end of last season after saying he wasn’t happy with the direction the club was headed. He had his request denied but will be able to leave for free when this season ends.

Barcelona said on Sunday they will take legal action against El Mundo. Barca’s last accounts showed their net debt had doubled to $592.24 million, while the club’s interim president Carles Tusquets said recently they had been forced to delay payments to players.

Barcelona denied any responsibility for the publication of the contract in a statement, adding they regretted its release as it was a “private document governed by the principle of confidentiality between the parties”.

The statement added: “FC Barcelona expresses its absolute support for Lionel Messi, especially in the face of any attempt to discredit his image, and to damage his relationship with the entity where he has worked to become the best player in the world and in football history.”

Messi, who described former club president Josep Maria Bartomeu reign as “a disaster”, had said in December: “I don’t know what I’m going to do yet.”

The revelations have come at a bad time for Ronald Koeman, with the blaugrana coming into their own after a difficult start to the season.

The Catalans are also still live in the Copa del Rey, where they face Granada in the quarter-finals, and the Champions League, where they face Paris Saint-Germain, one of Messi’s most persistent suitors, in the last 16.

Last Wednesday, Barcelona’s annual financial report has revealed that the Spanish giant have a mammoth debt due to the coronavirus pandemic and some big-money transfers in recent seasons.

The club revealed debt reaching $1.5 billion, along with the short-term debt of roughly $886 million. As per the release, Barcelona’s biggest area of spending is its wage bill, an area of spending that represents 74 per cent of the club’s income.