Lionel Messi and his father were ordered by a Spanish court to appear for questioning in September as part of an investigation into tax fraud allegations.
A court in the Mediterranean coastal town of Gava near Barcelona accepted a state prosecutor's complaint alleging that Messi and father Jorge defrauded the Spanish tax office of 4 million euros ($5.3 million).
The Barcelona and Argentina star and his father will appear before judge Anju Deb Rani in Gava on Sept. 17. That will form part of an investigation to determine whether grounds exist to charge them with tax evasion.
The court said in a statement that the judge's acceptance of the complaint was "a routine step."
"To move forward with the investigation a series of procedural steps will be carried out like taking testimony of the people necessary so as to clarify if a criminal offense has been committed or not," the court said.
If charged and found guilty, Messi and his father could face a fine amounting to 150% of the concealed earnings and between two and six years in prison, although an out-of-court deal is another possible outcome.
Messi's father said that the matter was merely a "difference of opinion" and mentioned the possibility that they would "reach an agreement."
"We are very calm because we have never not paid the tax office," Messi's father told Spanish radio station Cope.
"That there is a difference of opinion between them and our financial advisers (say this) is normal because there always are with those who pay large amounts to the tax office. I can assure you that what is paid annually is of two figures followed by six zeros.
"I know that there will be an agreement, but it bothers us that certain news outlets have led a slander campaign and generated expressions of hate. It is very cruel, but we know what to do when this is cleared up.
Court officials told The Associated Press that Messi and his father will have to appear in person for a session that will be closed to the public.
The timing of the court appearance could coincide with Barcelona's opening game in the Champions League, set to be played either on September 17 or 18.
The court accepted the complaint lodged by prosecutor Raquel Amada on June 12 accusing the pair of not paying the correct taxes from revenue earned from image rights on Messi's income tax returns from the years 2007, 2008 and 2009.
The complaint said they supposedly used a network of shell companies in tax havens such as Belize and Uruguay to avoid Messi's tax obligations.
Messi has denied wrongdoing. He has received public backing from Barcelona club president Sandro Rosell and former president Joan Laporta, who was in charge during the years of the allegations.
The 25-year-old Messi is widely considered the best player of his generation and one of the best in history after winning an unprecedented four straight FIFA world player of the year awards.
He scored 60 goals in the Spanish league this season before hurting his right hamstring, but it was still more than enough to guide Barcelona to its fourth domestic title in five seasons.
Messi is rated by Forbes as the world's 10th highest-paid athlete. He reportedly earned USD 41.3 million to June this year, with USD 20.3 million coming from his club salary and USD 21 million in endorsements.
He leads an apparently quiet life focused on his family - he became a father last year - and has never been linked to any unsavory episodes, making him a widely liked figure across the world.
The complaint lists Messi's sponsors that paid him revenues on image rights which he allegedly didn't pay taxes on. They include Barcelona, Adidas, Danone, Konami, Procter & Gamble, Pepsi-Cola, and Telefonica, among several others.