Mercury had been a long-time fan of opera, especially favouring Montserrat Caballé. In 1986, he mentioned on Spanish television that he would be glad to see her in person. They had a friendly initial meeting in Barcelona in February 1987. Later, when the city had been chosen for the 1992 Summer Olympics, Caballé, a native of the city, was asked to help with producing a song for the games. She summoned Mercury for the task. Mercury became enthusiastic about the project and instead of recording a single, she proposed to make an album, on which Mercury agreed. The song “Barcelona” had to be its opening song, to be completed by 1988, and to be submitted as a candidate for the 1992 Olympic theme (the selection was scheduled for 1988, 4 years before the Games). The recording was complicated by the tight schedule of Caballé. Thus to spare her time, Mercury recorded the song, also singing her part in falsetto. He would then send a tape to Caballé to prepare her for the joint studio sessions. (Source – Wikipedia)