Lionel Messi's most recent contract with Barcelona has been leaked by the Spanish newspaper 'El Mundo" on Sunday. Reportedly, its value is to be worth up to 555 million euros ($673 million) over four seasons. 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 138 million euros ($167 million) each season. It is believed to be the most expensive contract ever agreed with an athlete in any sport and Messi would have to pay about half of that in taxes in Spain. According to the report, the 33-year-old player has already secured more than 510 million euros ($619 million) of the total amount. Barcelona denied responsibility for leaking the document and said they would take legal action against the newspaper. "The club regrets its publication given that it is a private document governed by the principle of confidentiality between the parties," it said in a statement. "FC Barcelona categorically deny any responsibility for the publication of this document and will take appropriate legal action against the newspaper El Mundo, for any damage that may be caused as a result of this publication." The club expressed 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 did not make any public comments about the report, yet. The leak comes as Barcelona try to manage a huge debt created 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. Messi has been with Barcelona for nearly two decades, winning over 30 titles, but asked to leave at the end of last season after saying he wasn't happy with the direction the club was taking. His request was denied but he will be able to leave for free at the end of this season. Barcelona can move to second place in the Spanish league with a home win against Athletic Bilbao on Sunday.