Mourinho is alleged to have defrauded the Spanish tax authorities of €3.3 million while he was Real Madrid manager.
And he has now been summoned to appear in a courtroom on November 3, merely 48 hours before the clash at Stamford Bridge.
"Jose Mourinho has not received any notification with regards to the news published today," a statement from a prosecutor read on Friday.
"To this date, neither the Spanish tax authorities, not the public prosecutor have contacted Jose Mourinho or his advisers who were hired for the inspection process.
"Jose Mourinho, who lived in Spain from June 2010 until May 2013, paid more than €26m in taxes, with an average tax rate over 41 per cent, and accepted the regularisation proposals made by the Spanish tax authorities in 2015 regarding the years 2011 and 2012 and entering into a settlement agreement regarding 2013."
The charges relate to his image rights, with the Portuguese accused of defrauding the authorities of €1.6m in 2011 and €1.7m in 2012.
Mourinho is the latest in a long line of prominent figures who have been employed in Spain to face charges.
Cristiano Ronaldo, Lionel Messi and Xabi Alonso are just three players to have encountered issues with the law in relation to alleged tax fraud.