Nine Inch Nails and Anthrax have been added to the inaugural bill for U.K. rock/metal festival, Sonisphere, being held Aug. 1-2 in the grounds of Knebworth House in Hertfordshire, England.

Metallica, Linkin Park and Alice in Chains are among the acts already confirmed by London-based promoter Kilimanjaro for the festival, taking place on a site which has staged occasional major shows with attendances of over 100,000 since the mid-1970s.

Previous notable headliners have included Pink Floyd (1975 and 1990), the Rolling Stones (1976), Led Zeppelin (1979), Genesis (1978 and 1992), Oasis (1996) and Robbie Williams (2003). Williams drew 375,000 fans to the venue over his three-night run there.

In a statement, Anthrax guitarist Scott Ian said: "we are really excited to be making our only U.K. appearance at Sonisphere. We've been anticipating our return to the U.K. and we are honored to be a part of this amazing lineup."

In addition to Nine Inch Nails and Anthrax, Australian hard rock outfit Airbourne and re-formed post-punk outfit Killing Joke have been added to the bill. Other acts already confirmed include: Avenged Sevenfold; Bullet for my Valentine; Lamb of God; Machine Head; Mastodon; The Sword; Thin Lizzy.