Scene favourites chucked out cuts from 'Orchestra of Wolves' and 'Grey Britain' as their surprise appearance caused carnage in the Lockup Stage at Leeds.
The chaos kicked off before a note rung out in earnest as Steph Carter's sound-check was greeted with huge applause, confirming the hush hush appearance.
On 'Leeches', Frank Carter's rallying cries came from the midst of the crowd as the wild front-man threw himself and his mic into proceedings head first, stripping to his tattooed waist.
The craziest mosh pit was reserved for the manic 'Abandon Ship', with crowd surfers tossed around like rag dolls.
"No I never loved you anywaaaay!". Brilliant.
Leeds Festival 2010 continues with sets from Arcade Fire, The Libertines and more.