England is about to get an overdose of metal as Metallica are set to headline next year's Sonisphere Festival, and they're not coming alone.

Slayer, Megadeth, and Anthrax are also set to perform, reuniting thrash metal's Big 4, who played Sonisphere in Eastern Europe.  The bands join previously announced headliners Slipknot and Biffy Clyro.  The Sonisphere Festival takes place July 8-10 in Knebworth Park.