Was there anyone in rock that had the range and the voice of late Queen singer Freddie Mercury? While most know him from his work with Queen, he did step out to explore his voice in a different style with the solo album 'Barcelona.'

The disc, initially released in 1987, featured Mercury letting his operatic vocals blend with acclaimed Spanish soprano Montserrat Caballe, and on Sept. 3, 'Barcelona' will get a special four-disc box set 25th Anniversary reissue.

One of the highlights of the re-release is that the entire disc has been re-recorded with a full 80-piece orchestra backing the pair. In advance of the street date, a video featuring Mercury and Caballe duetting on the title track with the new orchestral backing has surfaced online (and can be seen below).

The 'Barcelona' re-release coincides with Mercury's 66th birthday (Sept. 3). Fans can also look for 'The Great Pretender' DVD and Blu-Ray that delves deeper into the singer's personal and professional life will arrive in stores Sept. 25, as well as a companion 'The Great Pretender' book coming in September.

Watch Freddie Mercury and Montserrat Caballe's Performance of 'Barcelona'

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