MADONNA is facing a backlash from Polish Catholics for scheduling a concert on a religious holiday.
The Material Girl takes her Sticky & Sweet tour to Warsaw on August 15 but it is the same date as the annual celebration of the heavenly assumption of the Virgin Mary.
Poland's ombudsman has now asked city officials to explain why she has been allowed to perform on the date.
Marian Brudzynski, the leader of Catholic group Committee for the Protection of Faith and National Traditions, said he plans two weeks of protests beginning July 31.
And the country's former president Lech Walesa previously claimed that he would "support" any protests against the performance.