As the rock and metal world awaits the latest news from the Download camp, festival rivals Sonisphere have added another big four to this summer’s Big Four!

Motorhead, Mastodon, In Flames and Parkway Drive will all play Knebworth this July – joining Metallica, Megadeth, Slayer and Anthrax at what promises to be an all-out riff-fest.

“We have been in the studio since October recording our new album and we can’t wait to come out and play the new song live,” said In Flames. “The UK has always been very good to us and we love coming back so this is something we really look forward to.”

Parkway Drive are just as stoked to be joining the Sonisphere party and vocalist Winston McCall said: “Holy crap they’re actually letting us play this thing!!! Sonisphere 2011!!! I don’t think we can really describe how excited we are to play and I think Jeff will probably die when Metallica play!”

With Biffy Clyro and Slipknot also confirmed as headline acts it’s over to Download to reveal the identity of their third and final headliner – with Van Halen and Bon Jovi tipped as favourites to join Linkin Park and System Of A Down at Donington.

And if you’re plotting your festival route this summer don’t forget to check our Dream Theater and the mighty Judas Priest at High Voltage in London – with Rob Halford and the boys making their final UK festival appearance on their farewell tour!

Sonisphere takes place July 8-10 at Knebworth House. For more information go to