The band performed a short, surprise gig last night at London's Tate Modern, in support of anti-poverty campaign, Agit8.
Playing as part of the campaign, which is taking place ahead of next week's G8 summit, Biffy Clyro performed on London's South Bank as a surprise act, having only announced their set hours beforehand via twitter.
During their short set, they spoke of how they were happy to be there, and how great a cause the Agit8 campaign is.
They opened their acoustic set with a cover of Rage Against the Machine's 'Killing in the Name Of', which they described as their 'favourite protest song', before playing a stripped back version of their 'Biblical' single.
Take a look at some fan footage here!
