Barcelona forward Lionel Messi and his father Jorge Horacio Messi are to appeal to the Spanish supreme court after being found guilty of three counts of tax fraud at a court in Barcelona.
A statement said lawyers for Messi and his father believed that the sentence was "incorrect" and "expect the outcome of their appeal to rule in favour of the defence."
It said lawyers Enrique Bacigalupo and Javier Sanchez-Vera believed the appeal would "show Lionel acted correctly at all times, as did his father."
Both Lionel and Jorge Messi were sentenced to 21 months in prison earlier on Wednesday, although neither is likely to serve any jail time.
Under Spanish law, a tax prison sentence under two years can be served under probation.
The lawyers "stressed that both Lionel and Jorge were aware of their tax obligations and, for this reason, approached a firm specialising in tax management for athletes" -- but the court "considered they were not well advised."
Messi and his lawyers respond to "almost symbolic" sentence pic.twitter.com/ARfF8ieLiN
- Sam Marsden (@samuelmarsden) 6 July 2016
The Barcelona court said the sentence could be appealed through the Spanish supreme court -- an option that is likely to take around a year to be resolved.
Messi was ordered to pay a fine of about €2 million ($2.2m), while his father was fined €1.5m.
The court heard a case brought by prosecutors who said Messi and his father used tax havens in Belize and Uruguay as well as shell companies in the U.K. and Switzerland to avoid paying €4.1m on earnings from image rights from 2007 to 2009.
Barcelona issued a statement in support of their star player, saying they felt he was not criminally responsible for the tax evasion.
"FC Barcelona gives all its support to Leo Messi and his father with relation to the sentence for tax evasion," the statement read.
"The club, in agreement with the government prosecution service, considers that the player, who has corrected his position with the Spanish Tax Office, is in no way criminally responsible with regards to the facts underlined in this case."
The prosecutors had called for jail sentences for the Messis, who both denied any wilful wrongdoing.
In court last month, Lionel Messi admitted he had signed many documents without reading their contents and visited a notary's office to set up a company to handle his finances without understanding what was going on.
When news of the investigation first broke in the summer of 2013, the Messis paid over €5m in arrears and extra charges. They are also believed to have paid €10m in taxes due on the image rights income for 2010 and 2011.
According to Forbes magazine, Messi earns a total of $81.4 million a year, making him No. 2 in their list of world's highest-paid athletes for 2016.