Spanish opera legend Montserrat Caballe has been charged with tax evasion for failing to declare $657,000 (£410,600) in earnings.
The 81 year old, who is most famous for her duet with Queen rocker Freddie Mercury on 1987 track Barcelona, is accused of hiding her true income by placing her earnings in a bank account in neighbouring Andorra.
The singer performed at a series of European concerts in 2010, which prosecutors claim netted her more than $2.6 million (£1.6 million).
The soprano insists she put her earnings in a foreign account because she was living in Andorra at the time.
According to court documents, Caballe used the account with the aim of "ensuring the (tax authority) Treasury did not have knowledge of her income and her true residency in Spain".
She is due to appear in a Barcelona court on 9 May (14).
Swinton herself is an ex-boarding school pupil.