According to the Universal Music store, Universal Music has set an October 11 U.K. release date for the "The Big Four: Live From Sonisphere 2010" DVD and Blu-ray containing footage of the June 22, 2010 Sonisphere cinecast from the Sofia, Bulgaria leg of the touring rock festival featuring the "Big Four" of 1980s thrash metal — METALLICA, SLAYER, MEGADETH and ANTHRAX.

As previously reported, Universal Music will release the "The Big Four" regular-edition single DVD and "The Big Four" deluxe-edition two-DVD/five-CD package in Japan on October 13. The deluxe edition includes an event poster, a poster from each band (four posters total) and guitar pick (subject to change). The box size is 20.5 x 15 x 4cm (subject to change).

METALLICA was joined onstage during the show by members of MEGADETH, SLAYER and ANTHRAX for a performance of the DIAMOND HEAD song "Am I Evil?"

METALLICA frontman James Hetfield, MEGADETH singer/guitarist Dave Mustaine and ANTHRAX vocalist Joey Belladonna took turns singing the song, which has been a part of METALLICA's live set for decades. The event marked the first time that Dave Mustaine had performed onstage with METALLICA since April 9, 1983. An original member of the band, he was fired just weeks before METALLICA recorded its debut album, "Kill 'Em All".

Mustaine, who was replaced by Kirk Hammett, went on to form MEGADETH and achieve worldwide success on his own.

He still harbored a grudge against METALLICA, however, with some of his feelings coming out in an intense scene with drummer Lars Ulrich in the 2005 documentary "Some Kind Of Monster".

According to Billboard.com, the Sonisphere cinecast from Sofia was beamed via satellite in HD to cinemas and was seen by more than 100,000 fans. It was distributed globally into hundreds of cinemas by New York-based BY Experience.

In the U.K. it was screened in 79 cinemas. "At the Odeon in Leicester Square in London there was a mosh pit, and at the end of the show they had a stage invasion, which is just phenomenal to even think about," promoter Stuart Galbraith told Billboard.com.