Lady Gaga's performance at the European Games in Baku is reported to have cost the Games organisers $2m (£1.3m).
Inside the Games claims that the fee was paid to the American singer in order to appear at the opening ceremony.
The 29-year-old performed John Lennon's 'Imagine' in front of a capacity crowd, and was only unveiled at the last minute.
Gaga has won six Grammy awards and 13 MTV Video Music awards throughout her career.
